All the time. I always seem to have a tune looping around in my head. Years and years ago I was at a banking drivethru and I was I though unheard singing a little ditty by the Beatles. Dirty Maggy Mae. Over and over to myself I thought. I looked up to see all the goils in the drivethru cracking up laughing. I motioned a little bow or nod to them and completed my transaction.
Yeah, I'm always doing it. Can't help it.