Charlie Conerly
It says a lot that Conerly retired for 18 months after he suffered a massive concussion. But then he decided that he was fine and returned to football. This was ludicrous behavior and could have cost him dearly. Health and safety standards were indeed different in those days but it still bemused.

Conerly had a great career with the Giants but he received more sacks than Santa Claus. In one game against the Steelers, he took a ludicrous 17 hits. The quarterback also served his country during World War II. Bizarrely, he never made it into the Hall of Fame (via Sports Illustrated).