1. I had a business dispute and other interpersonal conflicts, where knowing about human biases made me realize that my own perspectives are probably biased, and others' are as well but it's only human, which made me less indignant and prevented the conflicts from escalating more.
2. Learning the concept of moral uncertainty made me less angsty with not knowing what real morality is, and more ok with pursuing selfish and altruistic goals at the same time.
3. Eschewing conventional notions of success and doing things that are better for both my selfish and altruistic goals. (Not sure which rationalist concept this corresponds to exactly.)

Over on the "too small" end of the spectrum…

I wrote about how rationality made me better at Mario Kart which I linked to from here a while ago. In short, it's a reminder to think about evidence sources and think about how much you should weigh each.

More recently, I've been watching The International, a Dota 2 competition. Last night I was watching yet another game where I wasn't at all sure who would win. That said, I thought Team Liquid might win (p = 60%). When I saw Team Secret win a minor skirmish (teamfight) against Team Liquid, I made a new prediction of "Team Secret will win (p = 75%)". However, my original guess was correct: Team Secret eventually won that game.

I then thought about the current metagame and how, this year, any team can go from "winning" to "lost" with only a small error or two, and the outcome of any individual skirmish doesn't matter much.

I then imagined Bart Simpson repeatedly writing "I WILL NOT MAKE LARGE UPDATES BASED ON THE OUTCOME OF A SINGLE TEAMFIGHT" on a large blackboard and stopped making that mistake.

I think the major takeaway I've gotten from reading The Sequences is the vocabulary around updating beliefs, by varying amounts, based on evidence.

The thing you used to do, which was lacking in some way.

I used to be a loyal follower of Traditional Rationality. Emotions were the enemy, frigid logic and reason were my allies. Combined with a burning desire to win at all costs, it sort of worked. Since I wasn't learning from a specific person, I even managed to reinvent a lot of stuff from true rationality (in a hazy, unspecific sort of way). But the emotion thing... I was miserable, and my response to that was to bury those feelings instead of carrying out the introspection necessary to figure out why I felt so bad all the time.

The rationalist concept that challenged your habit.

Yudkowsky's vision of a unified rationality+emotions, and Kahneman's S1/S2 model of cognition, particularly the idea that S1 had something valuable to contribute.

I had heard all the standard "don't bottle up your emotions" advice before, but none of it addressed the fundamental problem that I wanted to win -- and as far as I could tell, emotions were nothing but dead weight. People who were emotional lost. They got angry. They cheated on their relationships. They flitted around life, tugged on a leash by their feelings. There was no focus, no coherence, no master plan behind it all. Just chaos. It seemed to me that the choice was to either be strong and cold, or weak and warm.

Reading about an alternative to what I was doing that didn't have massive immediately obvious flaws... that was enough to convince me to start the introspection process instead of ignoring how I felt.

What you do now.

I don't feel like crap all the time. Turns out there was quite the surprise waiting for me at the end of the rabbit hole (I'm trans), and now that I'm addressing the root problem, all the negative side effects are disappearing. I don't believe in a rationality vs emotion dichotomy anymore. I'd like to say that this has spread into my general behavior, but unfortunately it's only been a few months since my crisis of faith, and it takes longer than that. But when I catch myself trying to quash a feeling, or disregarding an intuition, I stop and ask myself whether this is the sort of situation where intuition would reasonably be expected to work well (frequent, rapid feedback, etc).

Rationalism has...

1. Helped me to get out of a cult.

2. Given me the mindset that any negative aspect of my life is (probably) fixable if I can just find the right angle to approach it from.

3. Kept me from falling into all kinds of political weirdness, and reminded me that My Guys shouldn't exist as such--I might have certain political positions which are shared by certain other people, but if I start thinking in terms of teams then I'm going to fall down a very bad hole.