h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Not to be rude or anything, but in my experience gym teachers tend to be people with more athletic ability than brains, but not enough there to make it in the field of professional sports, so they get a job teaching. They have to be able to look convincing in a warm up suit and whistle, and jog around easily in any sort of weather to shout encouragement to the students who don't care, don't try, or just plain aren't any good at sports. They also don't understand how anyone can not like sports or not be good at them.