[Removing these because all of PC doesn't need to know.]
More of a habit, but I make dumb faces when drawing. Usually to fit the expression of whatever I'm drawing. I end up sitting here, snarling at the computer if whatever I'm drawing is irritated, etc. :x
I use my teeth to rip the skin off my lips, sometimes to the point of it bleeding.
I have a habit of pushing my hair into my face to sort of hide behind it. Only on one side, though; otherwise it just feels unnatural.
This is a more recent habit. I keep messing with my left ear. It's slightly deformed (not enough to be visible, but if I run my thumb across that part, I can feel it), but I never noticed it until a few weeks ago. But yeah, whenever I remember, I feel the need to run my thumb over that part of my ear.