An old man and a boy were walking along a forest path.
It was a hot day, and they both felt like a good, cold drink.
After a few minutes the the boy and the old man came to a softly murmuring stream full of fresh, cool water. They knelt down and drank their fill.
"Thank you, stream," said the old man.
The boy laughed.
"What did you say "thank you" to the stream for?" he asked his grandfather.
"It’s not alive. It can’t hear you. It doesn’t understand when you say "thank you" to it."
"That’s true," the grandfather agreed. "And if a wolf was taking a drink, it wouldn’t say "thank you", either. But we’re not wolves, we’re people.
Do you know why people say "thank you"?
Think, now, who are the words really for?"
The boy fell into thought. He had plenty of time, for they still had a long way to go...