3. Conor McGregor
Irish MMA superstar McGregor had a meteoric rise to fame. However, his relationship with the UFC has had its ups and downs. One of the biggest came before UFC 200. First, the promotion booked McGregor to fight Nate Diaz in a rematch. But then he had a major dispute. He refused to engage in media duties because he wanted to focus on his preparation.

Then he pretended to retire as he played hardball with the promotion. Nonetheless, the UFC refused to back down. They pulled him from the fight and replaced him with Brock Lesnar. In the end, McGregor sat out for a few months after one of MMA’s biggest contract holdouts. He returned to action and defeated Diaz in a rematch (via FOX Sports).