I do this, and another "silly" thing I do is when I copy something to the clipboard, I often hit cmd-c three or four times quickly. I don't remember why or when I picked up this habit. I imagine maybe at some point I had a system or program that didn't always register the copy the first time? Or maybe it's just completely random. But I don't even notice I'm doing it until someone points it out and asks me about it.
