I got my wife and her sisters all obsessed about having the volume on an even number when I said it once just for a laugh, is a proper pain in the arse now!
The only things I can think of is all the blowers in my car have to be set perfectly so they're not sticking out and the fins are all straight.
Oh yeah, and when I was younger I used to go to sleep with the radio on sleep timer and it had to end exactly on the hour, even if I couldn't get to sleep for say 25 minutes I'd press the sleep button and set it again for the same hour!