10. B.J. Penn (2019)
Hawaiians adore Penn but even they must admit that his behavior became increasingly erratic in recent years. The former UFC champion went on a severe losing streak before the promotion released him. But his deteriorating results weren’t the main reason why they gave up on him. In the end, he left them with no choice after he had a street fight on the Big Island (via SCMP).

The Prodigy went to local tavern The Lava Shack where he had an argument with a fellow patron. Soon, it escalated and Penn bizarrely gave the man a free shot at his face. His aggressor duly obliged and KO’ed the UFC fighter. Penn soon woke up and wanted revenge. He stalked down his prey and shamefully put a beating on him. Finally, the promotion decided that enough was enough.