Johnny Manziel
Manziel is one of the most notorious failed NFL quarterbacks ever. The Cleveland Browns thought that he was the answer to their long-term QB problem. In the end, he left them with more questions than ever. Manziel had a great college career with Texas A&M. Some scouts feared that the Aggies star was too small for the league while others questioned his attitude and commitment.
But the Heisman winner arrived with a lot of hype. In the end, he partied more than he played and betrayed the trust of the franchise. His story is one of the most disappointing ever because everybody believed he was brilliant. Substance abuse and a terrible attitude brought his NFL career to an end after only two seasons (via Sportskeeda).
