I sniff a lot, it drives everyone else nuts, and I'm trying to stop it.
I also tap the mouse on the desk when I use a computer, or tap the scroll wheel with my finger, or something.
I also play with my slinky when I'm waiting for something (usually a loading time).
Upon arriving the attending doctor could find no abnormal physical symptoms other than extremely dilated pupils. After spending several hours terrified that his body had been possessed by a demon, that his next door neighbor was a witch, and that his furniture was threatening him, Dr. Hofmann feared he had become completely insane.