Everything in my life has a particular way it should be. Does my wife's head in because she is the exact opposite, no order or routine.
My most peculiar habit is that I count stuff over and over again. I count the number of lamposts between junctions every morning, I count the number of stairs in the house, the number of railings outside work etc even though I know they will be the same every time. I also count things like number of footsteps from the house to the car (28) and make sure that I always take the same number. It's not OCD though as I don't think anything awful will happen if I'm a footstep short.