A few months ago I caught one of my students playing with some cards when he should have been studying in class. I confiscated them and planned to give them back later on. I never did give them back to him as I basically forgot, and they held so little value with him that he never asked for them back. I jokingly hand them to kids who give a bad answer sometimes in an exaggerated manner like a bad football referee. A couple of weeks later, one kid handed me a new card with a new piece of student artwork. He was kidding and it was funny at the time.