A 10-year-old boy walked into a coffee shop and sat at a table. A waitress placed a glass of water in front of him. "How much is an ice cream sundae?"

"50 cents," the waitress replied.

The boy put his hands in his pockets and carefully counted the coins. "How much is a regular plate of ice cream?" he asked.

Some people were waiting at another table at the moment. The waitress was a little impatient. "35 cents," she said rudely.

The boy counted the coins again. "I want a regular ice cream," he said.

The waitress brought an ice cream, put the bill on the table, and left. After the boy finished his ice cream, he paid the cashier and left. When the waitress came back, she began to wipe the table. She felt very embarrassed when she saw what was on the table. There, next to the empty plate, neatly placed 25 cents - her tip.