This is a repository for major, life-altering mistakes that you or others have made. Detailed accounts of specific mistakes are welcome, and so are mentions of general classes of mistakes that people often make. If similar repositories already exist (inside or outside of LW), links are greatly appreciated.

The purpose of this repository is to collect information about serious misjudgements and mistakes in order to help people avoid similar mistakes. (I am posting this repository because I'm trying to conduct a premortem on my life and figure out what catastrophic risks may screw me over in the near or far future.)

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Placing zero value on the ability to look, dress, and act like a non-nerd. I seriously overestimated the effort and underestimated the benefits.

What are the bad things that can happen to you if you get accurately judged as nerdy, and how do they compare to the negative impact of having people assume all the wrong things about you?

What are the bad things that can happen to you if you get accurately judged as nerdy

This brings up an excellent point.

It's perfectly fine to be Packers fan, but I would judge a person who showed up to a wedding or funeral dressed as a cheesehead. I wouldn't judge them for being a Packards fan; I would judge them for disrespectfully violating decorum -- for choosing to signal that they are a Packards fan.

Projecting nerdiness is similar EDIT in that the first-order signal is not the harmful one. A nerdy appearance emits two important signals:

  1. You are nerdy
  2. You are a person who emits signals that they are nerdy

The second-order signal is the more negative and important. It isn't too bad if people think you are nerdy; it's bad if people think that you don't understand or don't care how most people perceive you. It signals a lack of self-awareness, or a deficient understanding of cultural norms, or blithe indifference. In my case, it accurately signaled all three.

Signaling my lack of self-awareness didn't cause bad things to happen; it prevented good things from happening.

how do they compare to the negative impact of having people assume all the wrong things about you?

No n... (read more)

I understand that it would be incorrect to show up at a wedding, funeral, or job interview wearing shorts, sandals, and a t-shirt with a bad science pun. Those are special occasions with different rules from the rest of your life, and fortunately they are rare. Why, in everyday life, would dressing like a nerd indicate blithe indifference towards anyone? Would I seem more empathetic and human if my shirt advertised a band instead, or had buttons? What are some common environments where looking like a nerd is a disrespectful violation of decorum?
Looking like a nerd is not a disrespectful violation of decorum -- disrespectful violation of decorum was part of an analogy about first-order and second-order signaling. Sorry that this wasn't clear. I edited my original comment, and will restate and rephrase the crux of the comment here. Let's take it as a premise that a large portion of people believe a nerdy appearance signals poor social prowess. Given the premise, people might emit nerdy signals anyway if: * They don't realize that they emitting nerdy signals, or * They don't realize nerdy signals will make many others less disposed to them, or * They don't care about the opinions of people who make negative assumption about people who signal nerdiness, or * They can't help but emit nerdy signals, or * (other reasons I won't list here) You will notice that all of these explanations indicate the person has poor social prowess. Unless there is common knowledge) that the premise is false, a nerdy appearance is evidence for poor social prowess. The expectation that people who look nerdy have poor social awareness becomes a self-fulfilling prophesy. ETA This line of reasoning isn't air-tight. Still, it's a strong reason why some nerd-friendly people take a dim view on a nerdy appearances.
I'm not sure this one belongs to the list: I'd figure that not having to care about strangers' opinion about you signals self-confidence, not “poor social prowess”. True that -- you can only countersignal to people who already know you. But those are normally the only people whose opinions about me I care about (except in job interviews, first dates, and the like -- where someone who doesn't know me well yet may affect me in the future), so why should worry about what I signal to anyone else?
I'm late to the party, but it's because you forgo new opportunities to meet people when you signal these things. For example, I knew a man who signalled nerdyness and had no social skills. Talking with him was uncomfortable and he would creep on women unknowingly, driving off other friends. Further, his lack of social awareness made it impossible to get rid of him once he was attached leading to an uncomfortable situation for all concerned. I had 3 other negative experiences from people who signalled nerdyness, each of which had serious problems. Essentially, by choosing to interact with new people who signal nerdyness in their dress I take on a higher than normal risk of having a negative experience. A large proportion of people have had an experience like this and do not wish to repeat it, so by signalling nerdyness you essentially drive those people away. Aside from that, you make use of the horns effect when you could be using the halo effect. The end result is that signalling nerdyness puts a pointless obstacle in the path of your life. Just signalling normalness puts you in a better position, because if you want to signal nerdyness to specific people you can just say "I play dwarf fortress" or something similar.
Empirically I think you are wrong. When I wear Vibram Fivefingers in public (with is a quite nerdy choice) it radically increases the amount of people that approach me.
I think we are using the term nerdyness to mean different things. When I say nerdiness I mean at least two of the following: poor dress sense, I'll fitting clothes, lack of deodorant, low personal hygene, excessively bad posture and bad hair style. What are you using the term to mean?
What if I've already met enough people? Dunbar's number is not infinity, so meeting people has an opportunity cost. I'm guessing the real problem was his lack of social skills, not his nerdiness.
Are the people you know now awesome and in sufficient variety and number? If so, I can totally understand not needing to know more. His problem was indeed his lack of social skills, but it was signalled by his nerdyess. The point here is not that there is a 1:1 comparison from these signalling characteristics to the end result, but that enough of the population thinks this way for it to alienate a large portion of the population when one signals in such a manner. That portion of the population includes many interesting people and should not be cast aside lightly. My life for example improved dramatically when I changed my signalling characteristics into a more confident and visually appealing style.
It's not just an issue of awesomeness and number but also time and distance. I have a pretty busy schedule these days so it would be nontrivial for me to find the time(/stamina) to hang out with more than a handful people on a regular basis; also, no matter how awesome someone is it'd be hard for me to be friends with them if they live halfway across the globe, so what matters isn't how awesome my friends are on an absolute scale, but how awesome my friends are compared to other people in my area. If I lived in the Bay Area and had more time than I know what to do with, things would presumably be different.
Sufficient is no absolute term, it is dependent on free time and other resources. Which is another way of saying I agree. With that said there is unavoidable attrition of friends from changing circumstances, locations, schedules and other factors that get in the way. I find it optimal to spend a certain small proportion of time seeking out new experiences with new people. After all, what are the chances that the people I currently know are the most suited to me out of the tens of thousands in the surrounding area? It feels like a betrayal to think such a thought, but I can come up with no good reason why I should listen to that particular emotion. Eventually things change and I see no reason to replace the friends who must leave my life with the first reasonably compatible people to come along, when I could instead take a proactive stance and do better. We decide the people we want in our lives
As far as first dates go, getting in bad relationship because you are fundamentally incompatible is a lot worse than just not making the second date. If a woman has a problem with me being nerdy, then it's no problem that the interaction ends at the first date. On the other hand full openness about who you are is very conductive to building trust and emotional intimacy. I don't think that true. If you engage in an action with full confidence and that confidence is clearly visible in your body language and most people who engage in the same action without much social confidence you can counter signal.
The things in bold -- I cannot put myself in the mindset where these things appear inherently bad. Would you mind explaining why should one make an end value out of respecting social and cultural norms? I suppose you could frame it like that too. Which are those good things? (Some guesses ahead of time: getting compliments on your outfits? Socializing more easily with certain segments of society? Modifying people's perception of you into something more positive, as an end in itself or as a means to something else, e.g. a promotion?) I assumed negative impact because I'm right on the other side of the pond: I have very good intuitions on dressing in a conventionally pretty, fashionable way, and yet this skill has always had negative value for me, as it influenced people's reactions to me in a way that worsened my interactions with them. But I'll expand on this only if it proves necessary.
One idea: Social power is contagious, so people want to associate with people that other people want to associate with. This leads to information cascades - one type of person has more power for some reason, so people want to associate with that type of person, so even more people want to associate with that type of person - and the "type of person" that this converges to gets called "normal". Another idea: By caring about social norms, you signal that you care about not having people disapprove of you, which gives the group power over you - "I'll limit my sheep's grazing of the commons, because I don't want to look bad."
Nitpick on wording: I wouldn't call wearing a suit to a wedding “looking like a non-Packers fan” -- it's not like non-Packers fans are all that much more likely to do so than Packers fan; I'd call it “not looking like a Packers fan”. By the same token, on hearing “looking like a non-nerd”, I think about an appearance that's significant evidence than you're not a nerd; I'd refer to an appearance that doesn't provide much evidence one way or another as “not looking like a nerd”.
This is excellent and is relevant to my thoughts. I defined it as self-hatred, but lack of self-awareness is close.
Seconded. A bit further: Placing little value or interest on personal style, not learning how basic style works, not owning any formal or even smart casual clothes at all, not knowing what terms mean and where they have broken up. This results in you going on really annoying (and maybe expensive) shopping trips under time constraint and makes you vulnerable to cultural guardians and merchants when you eventually are forced to figure out what the hell you are doing.
I will second this but with a twist: I tend to look really weird. But looking really weird and FANCY makes for a lot better and fun random social interactions. Put effort into your appearance, decide what you want to look like and what image you like to project, but that image doesn't have to be optimized for muggles unless you want it to be.

...that image doesn't have to be optimized for muggles...

Wizards who don't learn to interact profitably with muggles cut themselves off from most people in the world. Cutting yourself off from most people in the world is a life-altering mistake.

On the contrary: most people in the world are ignorant, useless wastes of your time. One SHOULD cut them out of influencing you and taking up your attention. If you can choose to optimize yourself for interacting with the average mathematician or interacting with the average person, you should choose the mathematician. But in any case: who said anything about cutting off? What exactly are you picturing here? Some sort of outfit that renders one invisible to anyone but bronies? That's not how clothing works, except in extreme examples.

People I value won't care if I have a non-standard hairstyle or wear clothing that doesn't fit well, I used to think. After cutting my hair and dressing better, I found that this is not the case.

To be clear, I think weird but fancy is great with the right audience. But being unable or not very good at presenting a non-weird image is a bad mistake. I underestimated how strong an image I projected to non-nerdy people. I think many other nerdy people underestimate the strength of the image as well.

I think there a difference between wearing clothing that just doesn't fit well and wearing the kind of weird clothing that can make a positive impression. Wearing Hawaii shirts for example is weird but something that people who consider themselves open minded but don't consider themselves as nerds can see as cool. I personally make the weird clothing choice of walking around in Vibriam Fivefinger shoes. In contrast to cutting myself off from other people they invite interest and people start conversation with me to ask me about them that they wouldn't start otherwise.
If. That would imply that optimizing signals for "muggles" automatically sub-optimizes for "wizards". And this is true for most values of wizard (goths, hippies, preps, nudists, professionals) but it's certainly not true when "wizards" = Intelligent, happy, kind, and effective people. You can signal allegiance to a subculture with a costume, but you can't signal a virtue. There is no reliable superficial signal for hidden virtues and abilities which are both universally admired and difficult / impossible to acquire. If such a signal were to exist and become well known, it would immediately become fashionable and thereby lose its signaling properties. The only honest signal for these traits is actual demonstrations of intelligence, kindness, actual displays of intellect, altruism, etc. As such, looking weirdly fancy isn't going to help you to that end. The way to surround yourself with smart/kind/effective people is to inhabit social spaces which attract smart/kind/effective people. Smart/effective/kind people (especially the elder generations, who happen to be the most useful to impress) are often still prejudiced in all the usual ways though, so you might still alienate them with your appearance. That's a really cold way to phrase that. I think that way sometimes, but only when I'm particularly unhappy or frustrated with people. The thought goes away when I remember that most people genuinely care about other people, and many care about me (Or to put it in game theory jargon, my preferences fundamentally overlap with most people's, and I consider agents who have those preferences intrinsically valuable).
I used to think that it didn't matter how I dressed, because everyone who wasn't dumb and superficial would just ignore my appearance and focus on other things in me. Then I noticed that I would feel an instinctive dislike towards people who looked bad, and an automatic liking towards people who looked good.
Did you conclude that your initial belief was incorrect, or did you conclude that you were dumb and superficial?
I think both.
It was the other way round for me -- I started instinctively disliking bad-looking people a few months after having started to optimize my appearance for dumb superficial people.
It almost certainly does, but that is a comment on 'optimal' and 'sub-optimal', not a claim that optimizing signals for muggles will not result in highly satisfactory wizard signals nevertheless. 'Sub-optimal' doesn't preclude awesome.
this is very true. My appearance is more optimized towards wizards but usually gets positive comments from muggles as well
Even that is less true in the hard sciences. I once had a professor in his mid sixties compliment me for my Clockwork Orange t-shirt after an oral exam, and most of faculty here seldom wears anything more formal than a polo shirt or a pullover.
For the purpose impressing people is most important for elder generations are not the most useful to impress.
What about being seen with lots of friends without looking like the kind of person who would get lots of friends regardless of intelligence, happiness, kindness and effectiveness? Countersignalling FTW!
Hehe, that is a clever/amusing idea. But even if it's true that this constitutes a meaningful signal (there are plenty of ways to get friends that do not involve intelligence, kindness, or effectiveness that leave no visual cues - like extroversion), it's a signal so subtle that I don't think I would pick up on it. Edit: It would work for simpler things though - we wouldn't be as impressed with David's intelligence if his muscles were as large as Goliath's.
I would have counted extroversion as in the same reference class as intelligence, happiness, kindness and effectiveness.
My reference class was "traits I would want in a friend". I don't really care about how often my friends feel the need to be alone. Extroversion is probably correlated with happiness - but then again, if we accept introversion-extroversion as intrinsic personality traits, who is to say that a lonely, socially awkard extrovert won't give the same test results as a sad introvert? Correlation(extroversion, income) supposedly has a inverse U shaped curve. Actually, the truth is I don't pick friends based on raw happiness was shorthand for general emotional maturity. I wouldn't want to be less friends with someone if they were depressed, for example - it's just that I don't want anger, anxiety, insecurity, and other sorts of aggression directed at me, and people who frequently experience negative emotions are more likely to direct aggression at others.
Most people in the world would be wastes of time due to the opportunity cost spending time with them would represent. "Useless" seems inaccurate, even without considering ways to stab people to death with their bones.
Are you sure you're not being a bit judgmental? Are you positive you're upholding proper value subjectivism when making this statement? What exactly are these people ignorant of, and why does it matter? What purpose are they useless for, and who's utility function contains this purpose? What are you optimizing for socially, and why do you suggest we do the same? You may say I'm being pedantic, but I don't think so. There are pitfalls everywhere on this subject. Although you might be correct, you shouldn't discount the possibility that you believe that statement only because you makes you feel like you're really awesome. If you changed your mind, you would lose a belief that makes you feel really superior, etc. Using terminology like "wizards" and "muggles" makes me think you've really gone off the deep end here. Besides believing this statement being a good way to feel superior, it's also a good way to shield oneself from social rejection. As a fundamental fact about how typical human hardware works, we can up-regulate or down-regulate how much we care about success with certain classes of people. If you think someone is really awesome, you feel more enjoyment when they accept you, and more pain when they reject you. If you think they're an idiot, you feel less of both. People like us tend to make a strong effort to match up our beliefs with reality, but most fundamentally our motivation system rewards us when we change our beliefs so we feel more enjoyment or less pain, not when the map becomes more matched up with the territory. Sometimes feeling better aligns well with updating to truer beliefs, but sometimes it doesn't. In this area, few things are more common than people grasping as straws trying to figure out why all the people who reject them are just idiots. Less pain that way. So here we are. You made a statement that contains a lot of unpacked information that if unpacked may demonstrate that you're being unfair, and at the same time I've identified tw
so I'm not being nice enough, and you want me to defend myself rigorously? Why am I suddenly held to these standards? I think it's perfectly obvious what I meant, and you don't want to accept or admit that most people aren't that great. I think you possess some views about the basic value of humans are afraid to let them go. So you have to attack me as being awkward or deluded in order for your own delusions to make any sense. I can and have explained elsewhere on these forums what I mean and I would gladly again, if you had simply asked what I meant. Instead you generate a multi-paragraph fantasy of myself, a person you've never met, involving rejection and inability to accept that rejection. This puts me in no mood to even really interact with you, let alone respond to your what I assume will be ever further rationalized attempts to prove my opinions wrong.
I didn't mean to accuse you of anything. I even said you may be correct. I was just pointing out that there are a couple common pitfalls on this subject which suggest one should require a higher level of rigor. It's indeed perfectly obvious what you meant, but what's not obvious is whether you're correct in your appraisal. If there were no pitfalls here, perhaps just the statement itself would be enough. But the presence of the pitfalls suggests that unpacking the propositions you made would be beneficial. I guess I learned my lesson though. I clearly worded my post in an unfair or offensive manner. Sorry about that.
In modern culture, you get a fair amount of weirdness allowed as long as you are capable of being normal when it counts and are not too self-indulgent with it... World of squibs.
But "people who should be ignored" and "people who don't care how you look" are hardly identical sets. If anything, they're more likely to be opposed than overlapping. The sort of people you want to deal with are usually those with enough merit to have choices in who they interact with, and thus they're naturally more picky.
I'm not against CARING HOW YOU LOOK. I'm against the view that caring how you look means you need to wear a suit or polo shirt and slacks or whatever the generic high-class look is.
There's other ways to care, but as a rule successful people are more likely to be worth knowing than others, are more able to be picky with their class distinctions, and are thus most likely to be worth emulating. It's not a universal strategy, but it's a common enough one that it's worth keeping it available.
I'm not at all sure that avoiding high variance strategies is always a great idea.
I am probably already cut off from most people in the world. A large fraction, possibly of a majority, of the world population can't speak any of the languages I can speak. But I'm only ever going to interact with a tiny fraction of all the people in the world anyway, so that's not a big deal. And if I have to choose whether to have 150 wizard friends or 150 muggle friends, I'll surely pick the former.
Define/taboo this term, please.

I don't think the boundaries of "nerd" are important to the mistake. If I were a and placed zero value on appearing as anything other than a , that would have been a huge mistake. I didn't realize how much appearance and mannerisms had pigeonholed me until after I changed them.

That's the point. Looking like a non-nerd sounds like selling non-apples to me. One possible way to “look like a non-nerd” is to look like a '80 skateboarder, but that wouldn't achieve your actual goal, so what you're actually trying to do is more complicated than that. And what do you mean by “nerd” in the first place? Someone with a very high IQ? Someone with poor social skills? Someone who studies or works in a hard science or maths? Someone who couldn't play football halfway decently to save their life? Someone who is into certain particular games and works of fiction such as (say) Dungeons and Dragons or Star Trek? Only a few of those things would I want to advertise the opposite of via appearance. (Your age, gender and social circle are also relevant to that.)
I consider this a successful taboo of what you meant, and it was quite different from the first thing I thought of when I read the word "nerd".

Not precommitting to be on my own before making a major life decision.

I once bought something in an New York shop through high-pressure sales. I looked at it and said something about how I would like to have it but I couldn't nearly afford it, and he asked me how much I would pay for it. Foolishly, I named a price; he looked insulted and said that it was far too low. I tried to explain that that was what I meant, that I couldn't afford it at any reasonable price, but he skilfully turned it into haggling, and I walked out with the thing and considerably poorer. I then resolved never to buy anything expensive without leaving the shop first, so I could just walk off if I changed my mind.

Many years later, I met up with my girlfriend's girlfriend for dinner and drinks so we could discuss whether it would work for her to move in with us. There were a lot of warning signs that it wouldn't, to say the least. I pressed her on things that were worrying me, and got wholly unsatisfactory answers. But we very often had good and enjoyable conversations, and this was one of those times. So at the end she sort of said "OK, that's all great, shall we announce online that I'm moving in?" ... (read more)

I had a related problem: performing a test without visualizing each of the potential outcomes.

I had been dating a guy long distance for about three months, and we were planning on moving in together. I had some reservations; my visits out there had been pleasant, but I wasn't sure that getting along for ~5 days at a time was that predictive of how well we would get along living together, and I had a bunch of specific doubts (such as his ability to have a difficult conversation in a way I felt comfortable with). I thought to myself "the way to deal with these worries is to give him a call." I did not think to myself "what would lead to me believing these worries, and calling off moving in together?" (Mistake 1.)

So, I call him, mention that I'm having some doubts and he explodes; everything's going terribly, and now also his boyfriend might be dumping him, and so I reassure him that I'm not dumping him and we're still moving in together, and that I had just been calling for reassurance. (This is why the mistake feels related: I made the decision during a high-pressure environment.) The call ends, and I realize "well, shit; that's basically confirmed my worries, and if I had planned ahead I would have known to call it off when he exploded." Then Mistake 2 happened: "I've already said we're going ahead with it, so I can't call him back and break up with him now."

(We broke up 3 months into a 12 month lease.)


Rationalising my feelings of social anxiety by adopting the view that I should not be socialising with my "intellectual inferiors" anyway: one must choose to be social or intelligent. When I entered university and met people I considered intellectual peers I was hardly able to socialise with them either because my social skills were so inadequate. Post-university it still took me a few years working at a low-paid job with a forced social element (working at a shop in a shopping mall) to kickstart my social development.

The converse mistake also occurs: see the second paragraph of this.
A large part of this is probably the homogeneity effect. When you are surrounded by similar individuals, you tend to be happier. Would a conservative person be happy in this setting?
Well, he did not say that “awesome” is a one-place word. ;-)
IF that's the case, perhaps the thing to "bottle up and export" is the idea that people should be pro-active about getting involved with groups which share common interests and values to themselves. Modern life puts a lot of diverse groups into contact with each other. Not only that, the information age makes it so that some people have culture imprinted from written material and no one in their geographic range shares their values. The internet can re-create the ancestral conditions of homogeneity. I'm all for conservatives having their church groups and stuff if it makes them happier and healthier, even if I don't agree with the values around which they congregate. But I'd be somewhat concerned about intensifying polarization of attitudes if this were to become a thing.

I once thought I'd skip learning to cook, thinking I'd specialize in something else and trade money for someone else's cooking. I've since learned to cook moderately well, and there are benefits:

  • Much better control of your nutrition
  • It impresses people; I can create dinner dates and dinner parties
  • It's tradable; you can swap your cooking for people doing other chores or buying food
  • Cooking is an activity with enjoyable depth, satisfying geeky tendencies to learn
  • Cooking is easy to learn, giving you success spirals
  • You can influence the nutrition of those close to you
Very inspirational! Do you have any resources in particular that helped you learn to cook?
I would recommend the book Ruhlman's Twenty ( It's not a cookbook, though it has recipes -- it's a thorough overview on the purpose of twenty basic ingredients in cooking (water, eggs, butter, salt, etc.).
Thanks for the recommendation.
My primary resource was The Four Hour Chef by Tim Ferriss. It isn't a recipe book (though it does contain recipes), but rather is a book describing how to actually cook, like how to do various techniques of cutting and braising, and what tastes go together, and how to learn what tastes go together. I recommend it, but this isn't the kind of high-quality recommendation you get from someone who's tried a bunch of things and has an informed decision about which one is the best. As I was working through the book, I asked a much more skilled-at-cooking friend for recommendations, and she said that On Food and Cooking by Harold McGee is highly regarded. I haven't checked it out yet.
Thanks. I actually checked out Four Hour Chef but never actually got around to any chefing before it was due. It looked pretty good for people with no cooking skills.
On "satisfying geeky tendencies to learn", the book "Cooking for Geeks" by Potter is actually quite good. It won't make you a chef in and of itself, but I now know enough to, say, know when to bake something at 375 versus at 350 degrees F based on the desired result rather than on what the recipe tells me. There's a lot of interesting tid bits in there and good a solid base of cooking information. It also has some good 'food experiments' to try, like cooking an egg very slowly wiht constant stirring at low temperatures in a frying pan. After about 20-30 minutes it turns into a custard-like substance. Not very appetizing, but it's really interesting to see how you can control what happens by changing the temperature.
Seconded. Learning to cook at a minimal level long before going to university has been a great asset to me, and allowed me to learn to cook well very quickly.

Being too ambitious in university and trying to do a three-year degree in two years, for essentially no real reason. Getting a burnout, recovering somewhat, and then trying to catch up by doing a lot of extra work each semester. Being able to sustain this for about three quarters of each semester, until I'd end up dropping several courses and accomplishing less than I would have if I'd taken a lighter course load from the start. Essentially repeating this until I'd finally finished my three-year-but-going-to-try-doing-it-in-two-years degree over a period of five years.

Be careful about how much you invest in a relationship. Whatever you might think at any moment, the probability that it will end in the future are relevant. I happened to make several life-changing choices in order to optimize the relationship with my former girlfirend, since we had been together for a long time and thing were sitll looking awesome. She dumped me abruptely, and I found myself navigating into a huge void of lost friends, lost hobbies, and a job that I like, but it's not the one I had always wanted to have (and had, before changing for the sake of the relationship).

Starting university with chemistry rather than computer science. Started on chemistry because I'd really enjoyed it at school, because my teacher was fantastic; realised I didn't actually like it at all. If I'd started on comp sci (and this was in 1985), I'd have done well, I'd have had much more money earlier, and my ridiculously intensive personal hobbies wouldn't have been affected.

tl;dr unexpectedly hazardous: good teachers.


Was that outcome predictable in advance?

Not at that stage, but it was definitely a mistake.
Hear, hear. I had a teacher who was good enough to get me briefly interested (this being in Israel) in Tanakh, my most hated subject.

1 I would say "Marrying the wrong person," but phrased that way, it's not really useful as a warning.* So let's go with "Marrying for the wrong reasons (e.g. because then low self-esteem and limited prior success with the opposite sex led me to settle far too quickly despite what should have been obvious warning signs). The emotional and financial consequences were catastrophic -- a lost decade of life, basically, And due having to children, another decade of not completely being able to escape their malign influence even after divorce.

*The more specific form "Not realizing I was marrying a borderline may be somewhat more useful. I know I've seen other Lesswrongers talk about similar issues, though I think they escaped before marriage and children.

2 Not actually doing any networking in college/grad school despite attending very prestigious institutions (due to introversion and cluelessness about the usefulness of this)

3 Not doing anything to deal with social anxiety much earlier, thus missing out on so many different opportunities.

In fairness to me, I'm older than the median LWer, and the Internet was a lot less helpful for finding the answers to life problems then than it is now.

What did you do to deal?
Not unlike habit formation, a significant part of this ultimately comes down to repeatedly telling yourself, "I am not going to be the kind of person who freezes up in social situations" until you eventually alieve it. This may actually require going to parties or other crowded situations and just standing around quietly the first few times. (As someone else once recommended on LW, working out is good in conjunction with this -- people are more accepting of the strong silent type.) Sooner or later, you'll luck into hearing a conversation you can't help but contribute your two cents to. Additionally, for me personally, OKCupid has been a huge blessing. I have much easier time approaching the opposite sex in writing than in person. But once you've done it in writing enough times, doing it in person seems much less intimidating.

Not seeing medical professionals as soon as medical problems arose. I now live with (likely) permanent chronic pain which may well have been preventable were the causes addressed at an earlier date.

The mental model that states that since all past problems have been inconsequential, all future problems must therefore be inconsequential is a problem here. Holding that mental state (my past problems have evaporated without issue, therefore my future problems will do likewise) is problematic because most people have not experienced enough major problems to draw on a meaningful sample size here.

If you do not mind, could you tell us what your initial symptoms were and what condition was causing them?

There's a strong case for not doing that. The lesson to be learned here is very general; but it's very tempting to learn only a very specific lesson instead.

Every time you go the doctor, you put yourself at risk of iatrogenic complications. Following the rule:

Every time you have a medical problem (this is a vague term), see a medical professional.

Is not very pragmatic.

5Paul Crowley
That's true! I wonder what the right rule is?
I'm unaware of a good answer besides "slog through the literature" or "pay someone to slog through the literature." The institutional filters that are supposed to help with this are quite poor.
If $20 isn't too much money, then you can "pay someone to slog through the literature" by purchasing a one-week UpToDate subscription.
Not sure if it helps, but I found this book extremely useful for my chronic muscle pain:

Mistake 1: Trying to convince others that I know more than I really do.

Mistake 2: Thinking that I actually know more than I do.

2mako yass
You have not explained why #1 is necessarily life-alteringly bad.

Not stepping back and thinking strategically about where to go and why before beginning a PhD program.

Because of a deteriorating relationship and problems in my current lab, I felt completely overwhelmed by the prospect of choosing a PhD. I was being told by my superiors that I had loads of potential and therefore had to get into the most prestigious institute possible. I therefore copped out of the difficult task of doing a PhD and essentially allowed my supervisor (who I knew was incompetent) to choose one for me. I never asked myself if I really wanted to do the research I was being pushed towards, if labwork was a rational choice for someone with my skillsets, or, more importantly, if I wanted to do a PhD at all.

Imagine my embarrassment when I start reading lesswrong and discover that stories like this about grad school are a stock example of irrational behavior...

A good, lightweight rule of thumb: before making a major life decision, spend at least an hour googling around for relevant information, especially from people who've done the thing you're contemplating. Chances are, your experiences will not be so different from theirs.

Then, seriously consider at least one alternative.

I second this mistake.
I also second this mistake.

Several popular comments say something to the effect of "I was too arrogant to just get with the program and cooperate with the other humans".

The biggest of my own arrogant mistakes was not taking CS/programming very seriously while in college because I was dead set on becoming a mathematician, and writing code was "boring" compared to math. Further arrogance: I wasn't phased by the disparity between the number of graduating Ph. D.'s and the number of academic jobs.

I found out in grad school that my level of talent in mathematics, while somewhat rare, was certainly not so exceedingly rare that real world considerations would not apply to me.

I've since changed my attitude, and I'm working on fixing this mistake.

  • Not taking the wisdom of nature seriously and, in particular, failing to appreciate the possibility that a considered intervention (e.g. polyphasic sleep) might do more harm than good.

  • Failing to do all sorts of things that I would have enjoyed merely because they involved some trivial inconvenience.

I've heard a few people say that polyphasic caused them lasting harm. Was that the case for you?

No. I haven't tried polyphasic sleep, which I mentioned merely as an example of the perils of ignoring the "wisdom of nature" heuristic. (I now realize that my wording didn't make this sufficiently clear.)

Failing to do all sorts of things that I would have enjoyed merely because they involved some trivial inconvenience.

Can you be more specific (if you don't mind sharing)?

This recent post by Ben Kuhn describes in more detail the phenomenon I was hinting at.

Majored in philosophy. I don't think I learned much worthwhile and it's makes it harder to get a job.

harder than having not gone to college or than a better degree?
A philosophy degree is definitely better than nothing. But I should have used that time to major in something more lucrative.
Potentially, but you may also have lost significantly in A)happiness and B)rationality. I think this may be more an issue of Harmful Options than actual significant utility loss.

Not taking risks of audio noise exposure seriously. Hearing loss is gradual, and tinnitus often starts as a temporary thing, so it's very easy to accumulate major damage before you realize it's a problem.

I carry around earplugs everywhere I go. It looks a bit weird, but I'm very glad for it.
I strongly recommend Etymotic earplugs. (I have this variety, I think.) While wearing them, basically the only effect is that you feel louder, and I always have them in my pocket, so anytime something gets louder than I'm comfortable with, I just pop them in, and I can still hear fine.
Me too, although they're for misophonia...
I'm probably risking this. Do you know how I can test for hearing loss, or how I can avoid tinnitus? I should do my own research, but I figured I'd check if you have tips.
Any good set of headphones can reproduce the whole 20Hz to 20kHz human frequency range, and any audio editor software can generate tone sweeps. The frequency response won't be perfectly flat but it will give a rough idea without paying for properly calibrated testing. Each ear can be checked separately. As for tinnitus, I don't know what influences permanence, so the safest assumption would be to avoid any sound exposure that causes it.

Taking advice because it's consistent and sounds reasonable, rather than because it's worked in practice.

-Taking the non-thinking NPC college route (going to whatever school was close enough to commute to, majoring in classes you thought were easy or letting your family influence your decision too much)

-Getting married extremely young because you think (probably correctly) that you can't support yourself, and then staying married much longer than you should have for the same reasoning (probably incorrect, by then).

-Spending most of college trying (and failing miserably) to take a large course load before realizing that you really just can't do it, and the only way for you to actually succeed is to only take two or three classes at a time so that you can do perfectly in all of them (i.e. stop trying to fight your perfectionism if it's causing you to fail, and just give in to it).

-Waiting much too long to start on a career track.

Upvoted for your mistake #3, which bit me as well (except it looks like you figured it out before graduating, whereas I didn't).
  • Failing to learn one's social norms quickly enough, and failing to make any falsifiable tests as to whether I was making mistakes. I was nearly asocial in elementary school, middle school was just weird, and then high school was this horrible mess of thinking people were being freaked out by me, or avoiding me, or not avoiding me, or literally anything. In reality, lots of people loved me and I didn't need to fear or be awkward about asking favors of people or asking to hang out with them.

  • Buying big-ticket items such as computer equipment by numerical stats only. Compactness, physical construction quality, compatibility, and battery life (which is remarkably often not really rated, or degrades significantly) may be as important or more important than non-numerical quantities. For the specific example of laptop computers, this means to go for low-end Macs, business-level computers, and if you desire Linux, Lenovo Thinkpads. And the worst part is that I didn't end up spending that much less than I would have for something with much better construction quality, etc.

  • Not having any friends or interests outside of STEM (during university), or even outside a very specific nerdy mindset.

Holden Karnofsky discusses an exaggerated version of your laptop mistake here.
Seconded. I still find this hard to undo, though I've realized the problem at least for a few years now. The problem is that your sense of what people value and think about is highly, highly skewed if you just hang out with nerds. Further, people outside the nerd community have a broader emotional repertoire. I realized that I had a narrow social circle when I counted how many of my friends can do "Integrate[Exp[-x^2],{x,-Infinity,+Infinity}]" in their sleep. You can use a similar test to figure out the narrowness of your social circle.
I would be very interested in hearing more about this -- my set of friends has a decidedly nerdy bias. Am I missing out on some feelings?
Some examples follow (caveat: these are generalizations based on small data-sets and each rule has exceptions. But I feel they're broadly true. Others, please support or contradict these 'rules'). 1. My non-nerdy friends are more open to physical touch, such as hugging, playful touches during laughter, comforting touches and so on. Nerdy friends seem to restrict themselves to handshakes; some find even handshakes awkward. 2. More inclined to solidarity rituals. Typical example: non-nerd enjoys sports. Nerd dismisses them as artificial constructs designed to provide conflict as entertainment, and therefore doesn't want to participate in the ritual. Another example: nerds will typically take most conversations towards arguments/debates; non-nerds will see conversation as a solidarity ritual and keep it's flow more towards participant enjoyment. 3. Larger amounts of empathy. Non-nerdy friends seem more open to non-judgmental empathy. Nerds tend to dismiss someone's pain simply because it's part of a larger pattern. Example: non-nerdy friend says the condition of disabled people in India/China is very sad. Nerdy friend: yes, India/China have large populations and therefore life is cheap; and revels in his ability to "explain it away". The conversation becomes stunted because the nerd has refused to participate in the "empathy-field" that the non-nerd wanted to generate.
1. My experience is exactly the reverse of this. 2. Agree. 3. Insufficient data for a meaningful answer. Query: do you refer only to empathy for large groups of distant people, or do you also suspect that nerds have less empathy for individuals in their social groups? It is not obvious that these would be related.
This hasn't been my experience. There aren't many people I consider good friends who aren't somewhat nerdy (though some are non-STEM nerds - history, the arts, etc.), but their amount of nerdiness, intelligence and STEM interest don't seem to correlate much with how emotional they are. And I'm not sure how I'd deal with being around people much more emotional than my friends are, even though I don't think I'm someone who'se unusually bad at dealing with that, and I do usually enjoy when people share their feelings with me. I wonder if going to a college where nerdiness is the norm is part of the reason for this? Maybe being cold has to do with being a minorty, rather than being nerds? There could also be selection bias at work here - sharing feelings is one of the things that makes me think I'm friends with someone rather than acquaintances.
That's a bit like saying "breaking a leg". Nobody does that intentionally. The mistake lies in what you make of it: being purposely asocial is not a good idea (especially through college age).
There were methods available for me to learn them. All I had to do was just some freaking low-risk costless empirical tests to calibrate it. My parents were telling me to. Once I reached college I did the tests and now am reasonably social.
Provide more concrete examples please.
Failing to ask people to spend time with me or work on projects together even when that was probably expected of me and (not in hindsight, but at the time) probably had few to no possible negative consequences.
Why is that a mistake?
Because humanity is the most complex and interesting subject that exists, and limiting yourself to a small portion of it is a good way to miss out on all kinds of interesting things.
That would also apply to not having any friends outside of your country, or outside of your generational group, or outside of your socio-economic class, or ... Also, “all kinds of interesting things” have opportunity costs.
I do have friends in all those groups, and consider them valuable as learning experiences in addition to the friendship. If you want to know people, cast a wide net. And knowing people has more value than you might think - politics, sales, even picking a neighbourhood to live in are all fields where a better understanding of human nature can be very valuable.
Knowing isn't the same as revelling in; can't we have Y without X? I already know what a kick in the rationals feels like, so why need I be reminded of that on a daily basis? There are cheaper ways to achieve that. I'm not going to go into politics or selling any sizeable amount of stuff to non-STEM people any time soon. Those are just not my comparative advantage. Why? I pretty much only go back to my place to sleep and shower (or other things that don't involve interacting with other people in meatspace); the rest of the time, I'm at university or at the canteen or at the bar or in the yoga class or at my girlfriend's place or in the streets downtown or wherever, so ISTM the only things to care about when choosing where to live (provided it's sufficiently quiet to sleep) are the cost of rent and the time/money/inconvenience/risk it takes from my place to the aforementioned places and back.

A selection of my top few regrets:

  • Getting into a relationship I didn't know how to get out of. (Result: I feel like years of my life have been wasted, and I was seriously distracted during an important period of my education.)

  • Not learning to code in college. (Result: Hard to say at this point, but probably financially costly and I'd feel much better about myself if I'd graduated with a marketable skill. It's definitely easier to learn when there's some time pressure and also TAs who can help you figure things out.)

  • Not taking advantage of moderately frightening opportunities that I thought would remain open for years but in fact closed within weeks. (Result: Details are personal, but I believe it contributed substantially to mistake #1.)

An interesting subset is the bad decisions you made that you knew at the time were bad, not just in retrospect, but did it anyway.

Last year, I had to choose what I would research in my honours year of my Computer Science degree. I actually remember thinking to myself, 'I'm going to use all of the techniques I have learned from LW'. I sat down for several hours, carefully analysing my situation, and came to the conclusion, I should research A. It is the superior option on every non-trivial metric I can think of. This is the rational decision. But then, I chose to research B, because I would have been embarrassed to have to explain my choice of A to my family. And that was it.

-Thinking I should follow advice I got from older respected people. The best advice I've ever had is that "lots of advice is BAD advice, or at least bad for you." I wanted to be open to criticism, and I'm into self-improvement, so I used to take advice really seriously when it came from a remotely intelligent source. Lots of it was contradictory, lots of it didn't apply to me and my specific situation and personality, lots of it arose from the special particularities of the advisor, and lots of it was just people saying vague things that sounded wise to feel like they had something to offer me. Instead, I started taking surprising/unusual advice (which really is the only useful kind, in my opinion) seriously only when it came from someone who knew me and my situation well, I understood the reasoning behind it, and I had gotten similar second opinions from other respected sources.

(Also, asking the advice of people I respected at a young age (12-19) instead of going online to find solid, well-tested, data-supported strategies to deal with my problems and questions).

-Doing research in a field that didn't interest me early on because I felt like I should be doing res... (read more)

See also

I don't know how to phrase it best so it fits here, but I feel it does, because it complicates my life regularly and therefore is pretty major: Not sticking to very beneficial routines that I know to be highly useful for my overall functionality in the short term and neccessary in the long term.

I know that I am happier and better-functioning when I regularly make journal entries and meditate. I am more productive at work, and I have more energy in my free time for other projects. Yet, I'm in a cycle where, when everything is going very well, I neglect both activities. Everything continues to go well for a while, then I get unbalanced, less energetic and overall less happy and productive, and only then do I remember that I already know what I can do to improve my situation.

For example, I neglected journal-writing and meditation in the past three month, which was a critical time because this left me with little energy to learn for a test (I'm currently doing a second M.Sc. to improve my chances of entering the economic sector I'm especially interested in). It won't have any unalterable consequences yet - if I fail on Friday, I can repeat the test next year, without having to study longer than intended - but it will make things more difficult and time-intensive next year, because I will have to prepare for the repeat tests as well as the tests scheduled for next semester. And I fear it's only a matter of time till this leads to bigger consequences (Seriously affecting job performance, for example).

This describes really well how I feel about the influence of epistemic rationality improvements in my life. They are often small and subtle enough that it is easy to overlook their importance in the short term. In the longer term the difference in clarity of thought between present me and past me is striking based on surviving material. It is only when doing this comparison that many of the differences actually become intelligible.

20 years of organized religion. Let me count the ways in which this is harmful.

Er... your count seems to go to zero. Is this deliberate humour, or bad phrasing?
It is a colloquial/humorous phrasing based on cheesy poetry indicating that the ways are countless.
  • 20 years of religiosity. (Oof!)
  • Quitting programming after 1 yr due to boredom.
  • Not studying math and science early (because: religiosity).
  • Going to college.
  • Not moving to the Bay Area at age 18.
What would you have done? How would you have moved to the Bay Area at age 18, and what would you have done for work without a college degree? Not skeptical; just wondering what your specific plan would have been.
Programming. Interning various places. Even just working at Walgreens, so long as it was in the Bay Area so I could encounter in person the important memes of startup culture + rationality culture.

I have made several serious misjudgements that are all instances of mistaking "I find this easy" for "this is easy in some general sense". Finding something easy is indeed evidence in favour of the thesis that it's easy, but it is also evidence that you are particularly good at it. I've mistakenly ignored the latter.

Dunning Kreuger effect?

Not autobiographical, all but one are people I know or have known personally. Which is not to say I have avoided all of these mistakes, but none of this is telling my own story. The ones about reasons for choosing college majors are speculation about other people's motivations, but are obviously mistakes whether they are the true reasons for people's bad choices or not.

Waiting through several years of depression and suicide attempts before telling anyone or getting it treated.

Not living on campus while you attend college, and also not having a car. (Edit: ... (read more)

On the other hand, waiting until you have your Ph. D. to begin breeding carries other risks. In this case, one should find an advisor that understands the stress maternity involves. It's entirely possible in some schools and disciplines to be practically done with classwork after the second year of study, and in some places it's possible to take a semester of unpaid leave without forfeiting the program.
Just freeze your eggs. Far cheaper than having children during the crucial early-career-building phase of your life. It honestly blows my mind that people rearrange their whole lives around having kids early instead of doing this.
It's not surprising to me that it blows your mind, since you've reduced a complicated decision with multiple dimensions of considerations to a single criterion.
My comment was very (perhaps overly) vehement. That said, the two main problems arising from increased maternal age that are most typically cited are: * Infertility and * Increased rate of birth disorders, both of which become very significant after age 35. By saving youthful genetic material, egg freezing solves these problems. However, in almost all online and in-person discussions I've participated in on the subject of maternal age, egg freezing isn't even brought up as an option and (this is more common in-person) people are either unaware that it exists or unaware that it is an established and reliable medical procedure rather than a fringe experimental one. Of course, the processes of retrieving the eggs and implanting them can be unpleasant and stressful, but I really do think that this is on a different order of significance than "if you don't get pregnant before a certain age your body may become unable to conceive a healthy baby." There are also a host of other lifestyle concerns, such as the desire to have children early when one is more youthful and energetic. However, those tend to apply to men as well as women, and again are more a matter of preference rather than a universal and insurmountable thing on the level of infertility after a certain age. Egg freezing isn't a solution for everyone, sure, but when I see women planning their whole lives around having children before 30 I do get frustrated when they haven't even considered egg freezing.
It's kind of like mini-cryonics!
And you don't have to take its efficacy on faith!
It's pretty expensive: $20k+. I'm not sure if that's expensive enough that most women should dismiss it out of hand, but it's enough that most who would want it can't afford it.
Does it really help your long-term income? I mean, if you're taking years off for family, does the choice of doing so at 20 or 35 make much of a difference to your income in your peak-earning 50s? Also, IVF is expensive in its own right, as well as being invasive and unreliable. Plus you're still left with raising kids at an older age, when you're less able to keep up with them.
Taking care of kids can be physically demanding (carrying them around, chasing them down, etc.) and I expect it's a lot easier when you are younger.
It's also a lot easier when you can afford assistance.
Wealth isn't an automatic consequence of age (or of a PhD for that matter).
Absolutely true. Neither is the ability to perform physically demanding tasks an automatic consequence of youth. We're talking about expected values, not guarantees. And I would certainly agree that someone who doesn't expect their career to increase their earning power over time would have a completely different expected-value calculation around impromptublue's suggestion than someone who does.
Are there risks other than age-related rise in mutational load? My cousin waited to have kids until she finished her microbiology PhD, and they seem to be doing fine.

Are there risks other than age-related rise in mutational load?

Not my field by a long shot, but this seems a decent survey of age-related health risks. In particular note lower average birth weight and higher incidence of very low birth weight.

I'm also aware of some evidence that having one's first child before middle age improves the outcome of having subsequent children during middle age.

My cousin waited to have kids until she finished her microbiology PhD, and they seem to be doing fine.


This was a rigorous personal experience; she had an anecdotally significant number of kids.
Not being able to have any children, or as many as you (later realised you) wanted.
Does the age-related mutational load issue even kick in before 30 to a significant degree?
I guess how bad a mistake that is depends on how bad public transportation is where you are.
My girlfriend was required to live on campus for her freshman year- when she moved out, her rent was $300 cheaper, the apartmant was twice the size, and it also seemed nice to have a freaking sink, and not leave the dog at home. And I would expect the cost of a monthly bus pass to be exceeded by gas alone. So why was this a mistake for you or your friend or whomever? It's not at all obvious to me.
The friend in question had to spend more than an hour a day carpooling to get to and from campus. (I don't think there were any buses from where he lived). This meant tons of waiting around for rides because college schedules are sparsely scattered throughout the day. This also meant going to office hours was a pain, and he couldn't (like I, and most other engineering students I knew could) get into labs in the middle of the night to finish assignments that frequently took longer than expected. That said, this probably isn't nearly as big a mistake in most people's cases, and I'm updating my original post to reflect that.
I've heard (but not experienced) that having to commute to campus, as opposed to being within walking distance, made people less likely to attend class regularly, and having to deal with any consequences of that. Obviously it depends on the person though. And on top of that, public transportation (at least in the US) can be slower and/or more unreliable compared to driving.
I fell into a similar failure mode. My program requires internships, but I hate the job-search process, so when I got an offer from a good company, I accepted it pretty quickly, even though it was so early that many of the companies that I had applied to hadn't started their interviews yet. I forgot to ask myself which aspects of the job I wouldn't like, and was too impatient to stop searching. (Disclaimer: if anyone happens to know where I work, it's really not a bad place. It's just not a good fit for me.)
Another specific failure mode I have heard about: Choosing a college because your lover is going to the same one.
I wonder if this is indicative of unequal relationship. Why isn't the lover going to the same college as you?
Maybe they're older, so chose first.
It's more a question of 'at least one person chose a non-optimal university to be together'.

The numerous mentions of soured relationships make me think that "not knowing some basic relationship failure modes, or not weighting the possibility that they will happen strongly enough" is another metamistake.

The plural of anecdote is not data and neither is the singular, but: I am ten years older than my partner, and this is my partner's first relationship. When we got together, we talked a lot about relationship failure modes and the hazards present in our situation (more than just the age difference), committed to voicing and understanding any concerns/fears/etc. that we experienced, and actually followed through on that commitment. We're only about a year and a half in, but so far this has been amazingly successful. It's hard to suss out how much is due to that commitment and how much is due to us apparently winning the compatibility lottery, but I do think there's a lot to be said for being realistic about failure modes and their likelihood. Long-term relationships, and especially cohabitation, require effort, and the sunk cost fallacy applies to them as much as anything else.

Perhaps not truly life-altering, but I'm currently somewhat regretting not having taken a formal course in Computer Science to complement my physics education. The problem with being self-taught isn't so much that there are gaps, but that you don't know where the gaps are, and you don't have the language to discuss (or Google) them easily.

Turning from myself to others, I see many physics graduate students who would benefit vastly from just one introductory formal course in programming - not computer science per se, just basic programming concepts. Flow co... (read more)

Undergraduate formal computer science education isn't that impressive, there isn't really anything similar to the mathematics fluency you need to painfully build up when studying physics. Software engineering does have an analogous coding fluency skill you can have, but formal education doesn't seem to really know how to drill that into you yet.

If you want to patch up a missing CS degree, just go read CLRS for algorithm analysis, SICP for general programming insight and the Cinderella Book for the theory of computation.

Then read K&R, because just about everything is C at the bottom and The C++ Programming Language (make sure to pick the latest C++11 edition), just to see all the insane complexities the pressures of backward compatibility, large-scale program architecture and high-performance programs will have you thinking about in real-world software engineering.

Looking at data structures more algebraically, as abstract types characterized by their introduction and elimination forms is another topic that's present in some standard CS sequences and can make one a better programmer. This breaks the habit of projecting intended interpretation of the data to its representation in computer memory, giving more freedom to design data structures for sparse data, that don't look like the data (which is their interpretation), but play its role (for example, binary decision diagrams). This is related to the statement/model distinction in logic, but the point of view of type theory is intuitively closer to programming practice. (SICP goes some of the way in this direction, but not in sufficient detail.) A standard treatment of (in particular) this aspect of type theory is [Pierce] or [Harper], which would go easier after something like [Girard, Lafont & Taylor]. Related intuitions can be developed by learning a language like Haskell [Lipovaca] and some category theory [Lawvere & Schanuel]. References: * Benjamin C. Pierce, Types and Programming Languages * Robert Harper, Practical Foundations for Programming Languages * Jean-Yves Girard, Yves Lafont, Paul Taylor, Proofs and Types * Miran Lipovaca, Learn You a Haskell for Great Good!: A Beginner's Guide * F. William Lawvere, Stephen H. Schanuel, Conceptual Mathematics: A First Introduction to Categories
Seconding the type theory recommendation. The formal CS education I had contained almost nothing about this, so it was all independent studying from textbooks for me anyway.
Not a problem with "self-taught" per se, as hypothetically you could read all of the textbooks covering the respective major (which would be faster and easier than if you were still a student and knew less).

Not making a special effort to move out of home when I started university.

Allowing akrasia to prevent me from applying for a single graduate position at any of the many companies that were hiring Computer Science graduates in my final year of study.

Allowing akrasia to prevent me from joining any clubs or associations at university.

Not getting a minimum-wage job for work experience when I was still young enough that the minimum pay for me was lower, giving me a competitive advantage.

Every time I lie, I regret it a little bit, as I wonder whether the long term trajectory of my life would have been different had I been totally truthful instead of 'polishing' the truth.

Not flossing for years. Once it is a habit not flossing will seem gross to you. Knowing that your future self will feel this way you should feel this way now.

I assume this is a mistake because there is evidence that flossing is beneficial. But this isn't a convincing argument at all: I feel pretty confident that if I decided to take heroin, my hypothetical future self would feel that not being on heroin is "gross." But knowing this does not convince me to take heroin.
That doesn't seem likely. "Terrifying" or "unthinkable" are likely. "Gross" is not. If your hypothetical future self felt that it would just be weird.
Hence the quotes.
Yeah but you should want to want to floss. You don't want to want to do heroin.
Well sure, but I still find your statement unconvincing as a reason I should feel that way. Once I conclude that I should want to floss (presumably because of the evidence it is beneficial), then that statement is a helpful way to install the habit. But it's not a reason that I should feel that way in and of itself. Maybe I'm just being too pedantic. Sorry.
No problem. My core assumption is that your reasons for feeling gross are well founded on evidence. This is probably only true in a very limited domain.

That thing I'm going to do next month that I don't even know about yet.


Don't do it!

3Paul Crowley
Unless it's something you're going to not do that you should have done!

Taking about twice as long as I could have at the university while it was obvious the entire time that I wasn't putting the necessary work into learning the heavy math I would need if I wanted to be a successful grad student. Should've failed fast with the research career aspirations and graduated as fast as I can. (You pick your own course load and usually work up to a Master's degree in Finnish university. There are grades, but generally only graduate studies programs care about them, so if you know you'll go to industry, you can load up on the courses and treat any passing grade as good enough.)

I wouldn't say any of these have been terminal, but I might reconsider some of the following things I did, if given the option:

  • Chose a major based on what I felt like spending four (...okay, five) years doing, rather than on what I thought I might enjoy spending any significant portion of my working life doing. In fairness to my past self, I don't think I had enough information when I was 18 to have made anything like an accurate guess, but maybe it was also a mistake to fail to attempt a solution to that preliminary problem.

  • Moved in with a signific

... (read more)

As alluded to in other comments, another interesting question is: given your past mistakes and your present circumstances, what do you expect your next "major life-altering mistake" will be?

Potential examples: continue to play football despite repeated concussions, getting together with yet another abusive boyfriend, relying on magical free will to get you through college until finally burning out and dropping out.

I'm starting a 100% commission sales job, and have had issues in the past with poor work ethic resulting in me almost failing out of school. I think I've outgrown them(this was years ago, and I've done some very hard self-motivated work since then), but if I haven't, I'm going to get hurt pretty badly by this experience.
  1. Not figuring out what I wanted to do before I finished college.
  2. Got a lot of sunburns between the ages of 12-20.
  3. Didn't take speech therapy seriously as a kid, had to work much harder later.

It's still up in the air but arguably dropping out of high school and then community college.

Trying to avoid personal vices by not acting or thinking like the people who had the vices I wanted to avoid. For example, wanting to be a great scientist, and suppressing this desire without realizing that it wasn't actually possible for me to aspire for one thing, dislike m motivation for it (fame and accomplishment), and try to come up with a better one- the actions conflict with each other, yet I really did think that the only reason I wasn't pursuing that path already was due to a disruptive home life. This is probably true, but to this day I can't te... (read more)


First, excellent idea!

Second, where do I start... Am I the only one who can list at least half a dozen life-altering sub-optimal decisions without pausing to think? Nothing catastrophic, though. I'll only mention a few school-related ones.

Undergrad: yielding to pressure to go for a comp. eng. degree instead of physics and not talking a chance to switch when one was available. Sure, employment options and salary are way better in comp. eng., and I never hated the work. But I will never find out whether I could have been a top x% scientist, rather than a so... (read more)

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Majored in Environmental Science; while it's not useless with respect to finding work, I feel that something like Chemistry would have had similar value for most of the same jobs, whereas Environmental Science is not valuable in all contexts that a major like Chemistry would have been.

Plus, it tends to lump me in with environmental activists, signalling-wise, while I am firmly of the opinion that if we actually want to solve most environmental problems, our solutions will have to be technological, not social.

  • Not living on campus with friends during college
  • Taking too many high-level math classes in my first year of college (including a really dense graduate abstract algebra course)
  • Not getting therapy while in college (rectified during grad school)
  • Not applying for internships in college (also rectified during grad school)
  • Turning down a promising summer research project right before my PhD. I thought that summer was a bit overloaded and I was going to do research during the PhD anyway, but it took 1.5 years of classes and qualifying exams before really getti
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  1. Not realizing that I was in pain (physical/mental/etc.) on a regular basis and dropping everything (or at least, as much as possible) and tackling them.

2, Thinking to myself that I would be able to do better/etc. on situation X in the future despite not changing anything or thinking hard about why situation X went badly in the past.

Two mistakes from when I was figuring out where to go for my PhD:

  • Not applying to more PhD programs. I limited myself to four because (a) I only wanted to apply to strong programs in my field, (b) I was very picky about location, and (c) I was too confident. Ultimately, this worked out okay, but I now regard the decision as arrogant and risky.

  • Not validating code and data used to decide which PhD programs to apply to and which PhD program to choose. As part of these decisions, I collected data about many things. For one of the more important things, I wr

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