Three doctors were sitting around talking about how brilliant they were and what life-changing work they had each done.  The first said, "I worked on a guy whose hand was crushed in a machine - it was mangled and just barely hanging on.  After I did surgery on him, he became a world renowned concert pianist."

The second said, "I worked on a guy whose leg was mangled underneath a caterpillar.  Now he's an olympic gold medal runner."

The third said, "That's nothing.  I worked on a guy who fell off a horse and nothing was left of him but his cowboy hat and an asshole.  Now he's president of the United States!"