I don't think I have real OCD, but I am very particular about neatness and organization to the point where when I vacuum, I do so in straight lines so the pattern left in the carpet is straight and uniform.
Reefkeeping has helped me stray a bit away from being bothered if something is not in its exact spot or done in a certain way. I when I setup my current tank I wanted to to have all the wiring for everything bundled in rigid wiring tubes, however my past experience in the hobby reminded me how much of a pain that makes it to remove and service and clean equipment and I have learned to live with a few dangling wires as long as they are out of sight.
I still do things that are unnecessary, for instance when its time to refill my kalk reactor, instead of simply opening the fill tube to add more. I must remove it and give it a thorough cleaning to remove the chalky build up on the sides.
I find that sense of peace though when I am staring at the tank and everything is happy and growing, gives me that "everything is okay" feeling that life outside of reefing isn't always able to offer.