I walked into a conversation last week about boxers who had some bad training habits. The guys who had good success but let's just say they weren't gym rats and could be lazy. I heard a guy say Foreman in the 90's was a "fat slob". Couldn't disagree more, he was simply a dude in his 40's who had not fought in a decade. If anything Foreman of the 70's was more 'lazy' imo. In approach or mental preparation.

Anyway...Tim Witherspoon. The guy just blew some serious talent and years.
Duran... After being a buzzsaw at lightweight he still found great success but the man could enjoy the rewards a bit much.
Jose Luis Lopez...May fall into the 'shoulda been' category but had some solid fights. He also got stoned a lot and partied hard.