What goes around comes around:
One day, a boy who was selling goods from door to door to pay his way through school, found he had only one thin dime left and he was hungry. He decided he would ask for a meal at the next house. However, he lost his nerve when a lovely young girl opened the door.
Instead of a meal he asked for a drink of water. She thought he looked hungry so she brought him a large glass of milk.
He drank it slowly and then asked, "How much do I owe you?"
"You don't...