Back in College we got an extra credit for doing something in class that nobody else could do. I decided to bring my guitar and play "In The Mood" by Rush....
I started playing it in front of the class and the first thing that happened is, right in the middle of the song, a girl said "can you stop tapping your foot'"
I didn't even realize I was doing it.
Ever since then I make a concious effort to never tap my foot when I'm playing.

Don't have a clue what this has to do with the topic but I always make a point of never tapping my foot when I play now.