Actually, having given this some thought, do have one.
When I rinse my face before or after a shave, I always splash my face an even number of times, I never finish rinsing on an odd number. I have no idea why, but that's what I always do, and it's definitely compulsive behaviour.
Going slightly off track, but still with the compulsive theme, when I get served a plate of food on a circular plate, before I start eating I will always rotate the plate unitl the layout of the food looks 'right'. If I can't get it 'right' I just eat it, and I never do it with elliptical plates.
Ian