A world-renowned heart surgeon was waiting for his car to be fixed. The mechanic, a jokester, called him over: "Hey Doc, I take these valves out, grind 'em down, and put 'em back in so the engine runs like new. You basically do the same thing for people, right?" The surgeon nodded. "In a way, yes." The mechanic grinned. "So how come I make fifty bucks an hour and you make half a million a year when we’re doing the exact same work?" The surgeon smiled, leaned in, and whispered: "Try doing it while the engine is still running."