My mom taught me (or drilled into my head, or contributed to my OCD) that I have to leave a building by the same door I came in. My friends/neighbors are all aware of this weird thing and they know that if I'm walking the dog and stop for a visit and happen to come in through the garage, don't close the garage door until I leave. My family is trying to break me of this habit. I went out through our garage door one day, was out for quite awhile visiting neighbors, and when I got home the garage door was closed. I went to the front door, rang the doorbell, and when my DS answered, sent him out to open the garage door. I have no idea why this has stuck with me, but I continue on with it!