I'm sure things like these are quite common in normal humans. I have a bunch of odd behavioural characteristics too that overlap with mental conditions: clanging, rocking and stimming, and until my mid-20s if I 'touched' something (including stepping on a tile-edge or crack at an angle) on my one side I had to symmetrify with the other side. But my life was fine. I was and am a successful adult with a job and life. Many of these things are probably just the normal variation of the species. I only found out these are named behaviours within the last year. Till then, it was just things I did sometimes or at some time in the past.

I imagine many others are also like this and have single or few such things. It progresses to being a disorder when people can't function, but when they can, it's probably just a trait.