I used to do most of these things in school also, most of the time it wasn't disruptive but I probably looked like I've had way too much caffeine or something. I tend to be so self aware of my body language, stance, what I'm going to say next, do next, especially in social situations, that I think the fidgeting is just a result of the underlying anxiety caused by failed social encounters in most of our pasts. But I also do some of the odder things when I am in the comfort of my own home, like violent leg shaking, or just occupying my hands with something all the time, since I'm a smoker I tend to light up out of impulse and find I didn't even want one a lot of times.