Whenever I am waiting for something to happen, I tend to move my mouse pointer around in circles on the screen - this always caught peoples attention and I've been asked plenty of times over the years if there was a reason for it. I always joked that it helped make things go faster by making the computer know I was still there and waiting - I guess I wasn't lying.
On my old 486 or first Pentium, when the computer would slow down and start trashing/swapping, the screensaver would enable itself while I waited... further crashing the computer. So moving the mouse did indeed make the computer faster ;)
Later I became lazy and just pressed the ctrl or shift key. I still do it when watching movies with mplayer or in something browser-based (that does not disable the screenlock automatically).
Same here. I've always told myself that it helps my eye keep the position in the text. (Especially helpful I'm distracted and turn away from the screen.) But if I really belived that, I'd be doing it consciously, whereas I becoming aware that I'm doing it usually makes me stop...
P.S. I'm also slightly(?) OCDish in preferring selections that are integer fractions of the paragrah length. E.g. in a paragraph of 6.3 lines I'll tend to select 2.1 lines at a time (not _that_ precisely of course).
