I have a very, very strong case of borderline OCD! So many little habitual things...
I "air type," using the appropriate finger to type out words as I hear or read them (the good side of this is that I'm an incredibly fast typist). The perfect words use each finger of each hand once.
I seek rhythms of three, four, five and (best) seven in all things, from music to sayings.
I not only count steps, I must start with my right foot and end with my left...uneven numbers of steps bug me.
On sidewalks, I pace my steps so that I get a rhythm of right and then left foot on each segment.
Two-colored tile floors (like in schools) make me think of chess boards, and I always imagine how the knight would travel across the room.
When I was a kid, I used to ride in the car and envision telephone poles as jumps, and imagine how a horse would time itself to jump each one...
...and there is so much more...at least I got over my stage when I had to get out of bed repeatedly to check to see if the door was locked!
Okay, okay...I admit, I'm downright weird.