Oh yeah I've had this one big time in the past. It sort of comes and goes, hasn't been bothering me much lately. But a few times at my old job I drove all the way back into work to verify I'd locked the door when leaving for the night even though I was _very_ conscious about locking it - I just wasn't was totally certain as I felt I needed to be.

If this starts bugging me again I'm going to start taking pictures of the locked doors for myself. :)