Twirling my hair.
I hate this habit. It makes me look vapid, and if there's one thing I can't stand is when otherwise smart people act vapid. OMG like totally.
I engage in this habit when I'm anxious about something, or deep in thought, so I often don't even realize I'm twirling my hair until some one (usually Husband) points it out. It annoys him, too.
It could be worse, though. I could constantly sniffle, or clear my throat. That irritates every one.
Oh, wait. I do those things too. At least during allergy season.
Pass a tissue.