A girl needs a room of her own.
— paraphrasing Virginia Woolf
It's important to control the amount of information people have about you, especially for creative tasks or in areas you expect you might want to change.
Defining yourself is risky, because then it becomes hard to change when everyone is relating to you as that. (Also for Keeping Your Identity Small reasons.)
Privacy helps avoid being defined as something, and it helps with managing how people define you when this can't be avoided.
A common idea is that other people judge you, assess you in their mind according to their standards, and there's not much you can do about how they see you.
In reality, people usually judge you according to the standards you give them.
People are complex — it's a lot of work to form accurate assessments. So when people tell us how to think of them, we generally believe them. (Often not consciously/intentionally, but what we think of ourselves is usually communicated in how we speak.)
All interactions require having a view of the other person and what they're about.
You need this to know what to expect from them, the role each of you play in each other's lives, and what they expect from you — how the interaction will go, what it will be based around, what's in the scope of the interaction and what's outside it.
So, it's a good thing we have some control over this!
We can have an idea of what we want out of the interaction and set the stage accordingly. If someone gets a false impression of us, we can intervene and correct it.
This has two difficulties.
One is that intervening when someone has a false impression takes effort. If someone has a lot of misconceptions about you, or if a lot of people have misconceptions, that can be arbitrarily difficult.
(This is related to "You can't please everyone": even if you could please anyone, it may be an intractably large problem to give every single person who knows of you a given impression. In practice, our impressions of people are never error-free.)
The other difficulty is: people change. Sometimes you no longer want the things your interaction used to be about. When people knew you as one kind of person, and you change, you have to manage their expectations — help them update how to understand you and your interaction with them.
If you're changing fast, this can be a huge amount of work. You may even change faster than you can communicate all the updates to everyone you have relationships with.
This comes up when you're newly developing ideas. Trying to figure something out, write a first draft, being in a transitional phase between two views, etc. Most people find it difficult to write if someone is looking over their shoulder. It's uncomfortable when you're just trying ideas and don't want them to 'stick' to you when they're just trials.
It also comes up when you're young. Children change very fast. This is the reason it's usually unwise for children's personal lives to be on the internet. Anything they post may end up defining them.
For example, if there's a photo of them playing with Star Wars, people might think of them as a Star Wars fan even if that was just a passing fancy that week. Which could also cause people to start relating to them according to stereotypes of Star Wars fans.
A similar thing happens when asking a 5 year old, "What do you want to be when you grow up?". This is a bad question. He might say "a doctor". Then at some point when he's 10, he'll have to explain why he doesn't want to be a doctor anymore, instead of just explain why he wants to be an engineer now. He has twice as much to explain.
And it's not just when he's 10 and wants to be an engineer. It's also next week when he wants to go to the bookshop, and he's directed to How Your Body Works instead of How Machines Work. Being defined in terms of "doctor" has now influenced his life in all sorts of ways. His answer to that question wasn't even his goal: it was just a guess, made in the context of his relationship with someone — he may not have even been thinking about it. (And rightly so.)
People still need to form assessments about you in order to interact with you. They need to know something. What should they be told? When should they be told things? Where do the lines get drawn?
- Resist letting other people define you. If you're going to be defined, define yourself.
- Decline questions, requests or invitations that set the framing of your interaction to something you don't like.
- e.g. "That's too personal for me.", "That's not my thing, I'm afraid.", "Thank you, but I'd rather not.", "Doing X does sound fun, but Y isn't something I can do. Would doing only X work for you?".
- (Or in the words of a friend: "Wow! Thank you very much for the invitation to the pub football night, but that's the last thing I can possibly think of that I'd want to do, it sounds god-awful." Said with friendly warmth and subcommunicating that it's just a personal preference, being blunt can work surprisingly well. If you're confident, friendly and not defensive, people assume everything is fine and they just update their model of you.)
- Tell people personal details when it is necessary for the shared problem or project (thinking of 'problem/project' in a very broad way, including social things, subconscious/inexplicit things, etc.).