Stupid things you do that you know are stupid but you do anyway as they make you smile for no explainable reason.
When I worked in Westminster a few years ago I bought a bike and started cycling in. My journey would take me down Whitehall and past Downing Street. When I passed Downing Street one day, almost involuntarily I looked over and whispered under my breath "good morning Mr Brown" (as he was Prime Minister at the time). Absolutely no idea why I did it, but it made me smile for some reason, and because of this I continued to do it.
I then got another job based in another part of London for a couple of years. But i'm now based in Westminster again, and my cycle in once again takes me past Downing Street. Now I say, quietly, to myself, "good morning Mr Cameron" as I go by. It still makes me smile, and I still don't know why.