Jon Jones
Jones became the youngest UFC champion in history when he claimed the light heavyweight title for the first time. It appeared as though mainstream stardom was an inevitability but it never materialized. That’s because Jones is a self-destructive person who can’t stay out of trouble (via N.Y. Post).
In recent years Jones committed several PED violations and suffered suspensions as a result. However, the worst case was when he committed a DUI offense and drove into a pregnant woman’s vehicle. He abandoned the scene in a terrible display of humanity and received intense condemnation.