A woman on my job told us that she had punished her son for hitting a girl at school. No TV, no PS2, no allowance, for a month or something like that.
So one day she and her husband were eating microwaved potatoes-au-gratin for dinner. And her son kept looking at them with a smile, although she didn't pay much attention.
Later, much much later, her son confessed that he had taken the potatoes out of the oven, peed into them, and put them back in. And mommy and daddy ate every bite. Yummy, yummy.