Dan was the doorman of a club in a big city. Everyday, thousands of people passed his door, and a lot of them stopped and asked him, What's the time, please?
After a few months, Dan said to himself, I'm not going to answer all those stupid people any more. I'm going to buy a big clock and put it upon the wall here. Then he did so.
Now people aren't going to stop and ask me the time, he thought happily. But after that, a lot of people stopped, looked at the clock and then asked Dan, Is that clock right?