I find quiet people that are observing interesting. It’s not that I’m interested in what they’re thinking or not thinking about, rather I relate well to it.
Back as a teenager, forced to go to parties (not much for parties), I’d usually find a fellow quiet, observing person and go to their side of the room. Briefly acknowledge each other’s existence as fellow observers, maybe a raised eyebrow to show the disdain for the whole extrovert atmosphere, but otherwise, we left each other alone.
Always ended up with a friend though. Never had to say a word. Just a fellow quiet person.