Today, one of my students was looking for a late w0rk assignment in the extra paper tray and he couldn't find it. I said, "If you bring the tray here, I'll look for it for you." He started to walk over and then stopped, looked at me, and said, "Wait, are you being sarcastic?" with a very confused look on his face.
Apparently, I am mean. But, I'm okay with it.