Whenever I really get into something or I get really excited about something, I start making small erratic movements with my leg. Suppose it's my version of wagging a tail.
Also, when I wake up in the morning, I always get up, turn on my computer, go back to bed and hit the snooze button. I started doing this because my old computer took like five minutes to boot up, now I just do it out of habit.
And finally, whenever I play a game or watch a movie/series alone, I sometimes loudly comment on things happening or my own thoughts. Kinda embarrassing if someone catches you doing it.
Captcha: That word is upside down.