It’s easy to assume tennis star Rafael Nadal has at least a little OCD going on. He always makes sure his chair sits perfectly perpendicular to the court. He always puts two drink bottles in front of the chair to his left, one behind the other, aimed diagonally at the court.
Before he serves, he uses his right hand to touch the back and front of his shorts, then his left shoulder, then his right, then his nose, left ear, nose, right ear, and lastly his right thigh.
At changeovers, he always waits for the other player to cross the line, then he crosses with his right-foot first. He folds a towel and puts it behind him, then folds a second towel and puts it on his lap. He takes one sip from the first bottle, then another sip from the second bottle, and puts them back in the same place with the labels facing the same direction.