People might think that you are joking and I probably would have done too, until I arranged to go for a bike ride with someone from the next street from me. He turned up 10 minutes late. I knew that he had OCD with regard to locking his front door so I asked if he had checked that it was locked - yes. Did he check that he had checked it properly - yes. Did he then check that the checking of the checking had been done properly - yes!
We went to set off past the end of his street but he suddenly turned right, saying that he wanted to
recheck that he had locked his door!!! When he started on the checking of the checking of the checking thing I rode off and left him.
He knew which way I was going and I rode slowly so he was eventually able to catch up but within a quarter of an hour he was fretting about his front door again!