Michael Jordan
When he retired at the peak of his powers in 1993, Michael Jordan had topped the NBA in scoring for seven consecutive seasons and had been named Most Valuable Player three times. But after leading the Chicago Bulls to three championships and the 1992 Dream Team to Olympic Gold, Jordan quit. To play baseball. His Airness signed on with a minor league team called the Birmingham Barons, with which he learned that hitting a curve ball can be a lot tougher than draining a fadeaway jump shot. So in 1995, he — ahem — quit baseball to return to the Bulls. In his second tour in Chicago, Jordan captured two more MVP awards and another three championship rings. Then he quit again, in 1998. Though he bought the Washington Wizards in 2000, he renounced his ownership and managerial role a year later so he could suit up for the mediocre club. But pushing age 40, Jordan had difficulty crashing the boards like he used to; he quit for good in 2003.