The kids had been begging for weeks, so their mom finally gave in and bought them a hamster. It was the darling of the family for about a week. The kids played with it and fed it treats, but then their interest faded. Finally, just as she had feared, the mother was the one who wound up taking care of it.
One evening, exasperated, she sat them down and asked, "Why did you even want that darn thing? How many times do you think it would have died if I hadn't been looking after it for you?"
"I don't know" her son guessed. "Once?"