A successful scientist was on his way to a seminar where he was supposed to give a lecture on his new breakthrough in research. His chauffeur saw his tired look and felt sorry for him.

"Sir, why don't you take the day off today", he said, "I've heard your lecture so many times by now I know it by heart. I can give the lecture and you can just sit back and relax."

The scientist thought this was a great idea, since he was sick and tired of giving the exact same lecture over and over again. When they arrived at the seminar the scientist put on the chauffeur's hat and seated himself in the back of the lecture hall. His trusted chauffeur walked to the podium and gave an excellent lecture showing at least as much confidence as the scientist would. At the end of the lecture the chauffeur asked,
just as his master always does, "Are there any questions?"

One of the professors in the hall stood up and asked a long question about a very complicated and highly theoretical matter. The chauffeur was panicking silently but finally managed to pull himself together.

"That, professor, is a very simple question," he answered, "in fact, it is so simple even my chauffeur can answer it."