My neighbor had been working with her son to get over the last hurdle of potty training: #2 in the loo. She had come up with an elaborate reward system whereby for 6 correct 'deposits' there would be a purchase of a much coveted robot toy.
The next morning, her son is perched on the potty, struggling away. She makes the comment that, "gee, you usually don't have to go poo until the afternoon..."
he responds with a sigh, "yeah, but I really want that robot."