I enjoyed this from The Proper Care & Feeding of Husbands, in which Dr. Laura relates a story told by a minister:
A grandfather was talking to his grandson, “Grandson,” he said, “there are two wolves living in my heart and they are at war with each other. One is vicious and cruel, the other is wise and kind.”
“Grandfather,” said the alarmed grandson, “which one will win?”
“The one I feed,” said the grandfather.