Fear
Maybe I'm crazy, but when I touch something that doesn't seem clean, my hand burns until I am able to wash it. Also, I have a fear of touching mail. That may or may not be a fear of bills, but I think it comes from living in New Jersey during that anthrax thing. What are your fears (that seem totally rational to you, but not to someone else)?
I'm neurotic about making sure the car doors are locked. I don't even like to lean against them when I'm inside the vehicle unless I just checked their status. In my head I have seen myself fall out of the car and onto the hot asphalt a thousand times, bashing my teeth and maybe losing a limb.
I don't know, maybe I'm like this because when I was eight, my grandmother's door opened on the interstate and we barely managed to catch her in time. Might have something to do with it.
Koukla, I bet that's EXACTLY why.