Well don't know what category this falls under but:
how about the student who had a recent blow to the head and when asked by ATC to climb, simply wound up the QNH to get the relevant altitude...............
or the walter mitty who declared he was an RAF tornado pilot who had ejected and was staying at the local RAF hospital (hit his head on the canopy apparantly as per goose in "top gun")and came from a totally imaginary squadron in cornwall and wanted a trial lesson.....but wouldn't take control and kept going on about 'scuds' but when we called the hospital there was noone of that name there......two weeks later the police rang the school cos he had run off with all his girlfriends cash....
or the instructor who came under "ground fire" from pikies with an airrifle who put a pellet through the canopy on short finals..
Or the laddish BMW whealer dealer who on an introductory flight said,"go on son, show us what this thing can do...its a bit tame"
and I subsequently spent half an hour cleaning the kidney beans he had projectile vomited out of the flap selector....
just an average day at the flying (school) circus.....!