Huh, tbh I didn't expect 'NPCs' to be associated with mental health issues (and autism) in this thread; I thought it moreso referred to people who are 'basic'/'normal'/'predictable' rather than 'quiet'/'doesn't engage much'.
I've personally found some people to be incredibly 'predictable', yes; like I don't even bother asking them things because I know exactly how they'll respond. And when I see the beginnings of some interactions, I go 'ah yes, I know exactly where this is heading -.-'. (Like the answers to this thread, though to be fair, I didn't exactly predict which particular person would respond in which particular way XD)
A big part of feeling others are NPCs I think is viewing people 'in aggregate'; like you look at someone, and they're not That Particular Individual but rather 'a webcomic artist'/'a QAnoner'/'a boomer'/'a therapist'/whatever. And you've formed a stereotype, which a lot of people will happen to fall into on a surface level (the stereotype came from somewhere, after all), and so you see them as just that stereotype because you never end up interacting with them in more depth, or in a different context (whether due to lack of opportunity or lack of interest).
And heck, I've observed patterns in my own behaviour as well 
I could think of a few 'types' people might peg me as after reading a few of my posts, and think they can predict everything I say.
... heck, why not XD To anyone who cares to vote (anonymously), did you predict I'd respond the way I did to this thread?
- Yes
- No
- Ehhh ... something similar? But there are also some things I didn't expect?
I am curious though:
What are those strange things? :0
Ah, right, also:
We do get kind of 'indoctrinated' into following a specific path in life; we get trained out of 'just doing things' and spontaneously exercising our agency, and that's why people don't do much 'out of the box'. We need to ask permission and go through the proper channels to do anything too unusal/'big'/'important', and that's why no-one (seems to) think to animate their webcomic by funding one cut at a time instead of licensing to an animated studio, or being homeless by choice, or making a 'fake let's play' of a video game.
The probably have thought about it, they just didn't think it was possible, so they didn't try. So you never see it.
Actually, how about this: how would you convince someone that you're not an NPC? (I don't think you are one since I don't think anyone is an NPC, but just out of curiosity :P)
