It seems that most people seem to have one or two obsessive-compulsive things that they do or habits they have.
For instance, I cannot touch a potato chip with my thumb. If I accidentally do, I have to wipe off any salt or flavouring off it.
Also, whenever I'm hanging out the clothes for drying, anything that requires more than one peg has to have matching colour pegs. This goes to the extent of a pair of socks must be next to each other with the same colour pegs. But this has become habit and I do it without even noticing now.
So what's your little bit of OCD?