Thanks for all the great replies!!
Reading these replies makes me realize how little I've actually analyzed this aspect of myself. Some of the things brought up don't strike a chord with me at all, some very much do. Other than knowing, viscerally, it's difficult to determine what does and does not make me anxious. I suppose if there was too much logic behind it, it wouldn't be anxiety at all. It's so fascinating how different we all are and how differently and randomly this sort of thing manifests.
Several people brought up social interactions, small talk, or chit chat. Those don't bother me at all. I'm not saying I love it, or am good at it, but I have no anxiety about it.
Might there be some kind of subconscious thought process going on like "I'm wasting this person's time, I don't really need their attention, in some way I'm not worthy of their attention, they have better things to be doing than talking with me, etc."? And when you do have a very good reason to be taking their time you have no anxiety about doing so?
This strikes some chords with me, but it doesn't feel quite right either.
or even something similar to "you're not doing it right" - like I imagine calling someone and asking for something and having them chastise me for asking, because "that's not how it's done" or something. Like everyone knows the right way but me and I'm the dumbass that made this stupid move. The thing is, that could be a legit fear under some circumstances, but I basically feel that way all the time
I think this is very close to exactly what I feel. The situations where I don't know exactly how this works, but the other person clearly does. Walking into a restaurant that works differently. I guess a lot of it is living in fear of someone (even, or especially, a total stranger) thinking I'm a fool, or telling me "no, why would you even ask that."
I actually feel pretty good, just having named it more precisely. It is something that i can easily cope around. I could just walk into a restaurant and force myself to just say, every time, "I've never been here before, how does this work." And also, thinking about it I am most comfortable when I'm traveling and I know I stand out as a tourist. Walking into a place in Indonesia, everyone knows I'm an idiot tourist, and I know there's nothing I can do to embarrass myself.
Again, thanks all for the responses and insights!