Johnny Manziel
Manziel almost singlehandedly changed the Aggies’ fortunes on his Heisman run. His stunning college form at Texas A&M persuaded the Browns to draft him in 2014. This wasn’t a given because his attitude and stature put off many other franchises (via AP News).

But Cleveland decided that it was a worthwhile gamble. In the end, they threw him away like yesterday’s garbage. Manziel threw seven touchdown passes and seven interceptions in two seasons. His substance abuse problems took control and he fell out of the NFL.