I wipe the toilet seat with toilet paper before I sit on it. Even if it's my toilet and I was the last one to use it. I also have to line up my mouse pad with the edge of my desk. They're the only OCDish things I do.
I have an OCD of starting over. On pretty much everything. Especially with the internet and numbers is mainly what causes it. I have like more than 500 Gmail accounts because an email doesn't have a right date or time; I reformat my PC almost daily because I installed or downloaded something I don't want. I have like probably 25ish CF accounts, 7 MSN accounts, 6 Facebook accounts, ect. Everything has to come on a 5. 0, 5, 10, 15, 20, ect. Volume on my TV, settings, email date/times, friends on Facebook, ect.