Unfulfilled Potential

First topic message reminder :

Throughout the history of boxing there are stpries of fighters, who for one reason or another were unable to fulfill the career paths that many had thought they would in the early part of their careers. Whether it was a mental flaw or physical flaw that held them back. Or even a wrong fight at the wrong time of the career I.e Taylor vs Chavez.
Fans often speculate how Hearns could have been the best of the Fab 4 if only he had a cast iron chin and that's just a quick example I'm throwing in to get the ball rolling.
So I'm looking to know which fighters were held back from achieving their full potential due to one character flaw?
Cheers

Either conteh or Naz from the brits and any of the heavyweights from Tysons era - were they not drug addled/ arrogant or just plain lackadaisical.

Baby Joe Mesi - would, could and with the likes of Maskaev running around - arguably should have gone on to become World champion.

Herol Graham. Wonderful talent - could do so much. And today all we remember is "that" punch from Jackson and the arborescent fall.

I had to google that