A bus filled with passengers was speeding down a hill, and a man was chasing after it.
A passenger leaned out of the window and shouted to the man, "Buddy, forget it! You'll never catch it!"
"I have to catch it," the man panted, "I'm the driver of this bus."
(Note: Some people must work with extreme diligence, for if they do not, the consequences will be tragic. Yet, it is precisely because they must give their all that their latent instincts and hidden qualities are eventually fully revealed.)