Well I was only notified of it recently but a friend asked me why I would sometimes stare at my forearm and flex it. Confused at first I managed to catch myself doing it and it was because I would open and close my hand slowly (palm facing up) because I hurt my wrist a couple of weeks ago and I can still feel a dull pain in it. Clenching and unclenching my hands kind of allows me to feel where it hurts still but it does kind of look like flexing.
I also don't strictly affirm to things when people ask me stuff, I'll usually say "I guess" or "maybe" before I say yes or no.
Oh and sometimes I'll make this weird noise, it's hard to describe, but the way it's done, is you put your tongue to the roof of your mouth and suck in air to one side until it makes this weird suction sound although I can make two quick sounds like that pretty fast and tend to do it when I'm doing homework or something. Not sure why and it seems to be the only time I notice myself doing it... which makes me wonder if I'm inadvertently freaking people out elsewhere.