An architect watched a mechanic remove engine parts from his car to get to the valves. A surgeon, waiting for his car to be repaired, walked over to observe the process. After they introduced themselves, they began talking, and the talk turned to their lines of work.

"You know, doctor," said the architect, "I sometimes believe this type of work is as complicated as the work we do."

"Perhaps," the surgeon replied. "But let's see him do it while the engine is running."