strangers
I can only assume this for myself as I only know my mind and not even I know everything about myself, but every person is a puzzle, every new experience, every interaction, every action towards others and or me, puts a new piece on the puzzle towards knowing that person.
The image that you can estimate can only come from your past experiences and/or pre-conceptions, there's no person in the world that doesn't do this because it's kinda like a defense mechanism, if someone likes football/soccer, you can kinda expect that they like beer, if someone is very assertive and direct, you might expect that they either have their life well put together, or they are overcompensating for lack of confidence depending on previous conversations or how they act.
These preconceptions form what I like to think as whole other person, of course, with time this person will be very close to the real one, but point stands that sometimes even someone you think you know pretty well can vastly be changed in your perception, either by seeing something you've never seen before about them, or by simply they themselves changing over time without you noticing (which is I think a whole other topic tbh).
This also happens to You fr, there's a bunch of versions of you'll spread through people's minds, and some of them will have something about you that you wouldn't even notice, you can be the most self aware person in the world and you'll still uave something you do automatically or without even noticing. Which gets me to the point of this post, I think you don't truly know yourself, until you start to notice how people notice you, you might have your values, your way of talking, your mannerisms that you care about and constantly think about, but that automatic part, the one that you do always without noticing, that one will only be ever known to you of something draws your perception to it, and it's either revisiting past experiences or thinking about your exterior that you'll really know.
fyi: I'm not saying you should keep appearances though, I already talked about how I don't like that as much, even though it's kinda important to properly pass to somebody what you are about