Back when an ice cream sundae cost much less, a boy entered a coffee shop and sat at a table. A waitress put a glass of water in front of him.

"How much is an ice cream sundae?"

"Fifty cents," replied the waitress.

The little boy pulled his hand out of his pocket and studied a number of coins in it.

"How much is a dish of plain ice cream?" he inquired.

Some people were now waiting for a table, and the waitress was impatient. "Thirty-five cents," she said angrily.

The little boy again counted the coins. "I'll have the plain ice cream."

The waitress brought the ice cream and hurried away. The boy finished, paid the cashier, and departed. When the waitress came back, she swallowed hard at what she saw. There, placed neatly beside the empty dish, was fifteen cents, her tip.