
12. Leo Randolph
Randolph won Olympic gold at the 1976 Games in Montreal. Boxing fans saw the flyweight as a potential legend. His amateur career was up there with the very best. But then he switched to the professional side of the sport, and things started to go wrong.

First, he went 16-1, winning, losing, and reclaiming the WBA Super-Bantamweight strap. Then he took on Sergio Palma but the Argentine battered him until the stoppage in the fifth round. Randolph retired immediately after the crushing loss. The 22-year-old admitted that he lacked the killer instinct.