Back in sixth grade, we used to have recess out in a gravel parking lot. I'd pace in figure 8's till I wore a path in the parking lot. I even got a couple other kids to join me every now and then. I don't think I was letting off steam or anything. I just wasn't really interested in the soccer game all the other boys were playing.
A couple months ago, I was visiting home, and was working on something and rocking back and forth. My mom asked me why I was rocking, and my answer was something about "concentrating". I didn't really realize till then that this was unusual for a normal person. I've noticed since then that I can't really sit still. I have to wiggle my leg or spin the chair next to me or something like that.
I guess I've just recently discovered that I'm "stimming". I'd never heard of that word before I met WP, but it makes so much sense to me, now. It makes me sad, though, that it's so unusual for the general population.