14. Anderson Silva
‘The Spider’ changed mixed martial arts when he entered the UFC in 2006 and proceeded to dismantle Chris Leben. From there, he went on the longest winning streak in UFC middleweight history with 10 incredible title defenses. However, his back-to-back losses against Chris Weidman changed the course of his career. Overall, Silva’s tenure in the UFC went on far too long. He left the promotion at the age of 45 and still refused to retire.
In fairness, it’s his body and that has to be respected. But at the same time, he won just one of his last nine fights in the promotion with one no-contest. There are few things sadder than seeing a former superstar suffer a beating at the hands of a lesser talent who wouldn’t have stood a chance against him in his prime. However, in combat sports, this is exactly what will happen if fighters continue to fight for too long.