Delonte West and LeBron James
It takes a lot to rattle James because he’s one of the most successful athletes in U.S. sports history. However, West succeeded and may have negatively influenced the Cavaliers star in the 2010 Eastern Conference semifinals. Bizarrely, James had one of the worst postseason displays of his career but there’s a good reason why.

He had a serious problem with West, one of his Cavs teammates. Allegedly, West had an affair with James’s mother Gloria but the superstar didn’t know about it. Then the news emerged and humiliated him because everybody was talking about it. It was one of the lowest points of his career and they became bitter enemies (via Bleacher Report).