Often, I will unconsciously curl my fingers inwards, and tap them individually against a surface (i.e. my leg, a table, etc.) Just recently, I realised where this random habit has stemmed from - most probably from growing up with a piano at home and near to hand, and which I played from a young age. It's almost like my fingers are so used to being in that position that they play silent tunes of their own accord. What I also realised was that this is something I will start up at any point in the day - it doesn't seem to matter if I'm feeling flustered, self-conscious, stressed or completely at ease. But on the whole, I think it's a comfort thing. When at home I find myself turning to the piano when I'm feeling unsettled, restless or down. It's almost like a therapy - I hammer out the negativity while running my fingers over the keys, and turn it into beautiful music (well, I can't say my playing is beautiful, but they make moderate entertainment...) I guess it's the same when I'm nowhere near a piano, and my fingers start to play nevertheless.
I'm very tired, and hope I am still making sense in this analysis of my own personal body language. I'm not even very sure why I am writing about this (for want of a subject maybe?), but hope it makes interesting reading. What strange habits do you have?