When I clean the bathroom sink it must send out some primordial signal to him that it is time trim his mustache and leave the clippings in the sink. He does it every time I clean the freaking sink! He is like a dog marking its territory! I tested my theory by not cleaning the sink for several days; he never trimmed. The day I cleaned it, he was in there within an hour.
A few years ago he got really sick and had some brain issues. He is different. There are little things he does now that he never did that can put me over the edge but I chalk it up to the illness and let it go. If I didn't, his picture would be on a milk carton.