Geno Smith and IK Emenkepali
Everything was fine between these two men until Smith broke Emenkepali’s trust. The Jets linebacker invited Smith to attend one of his summer training camps. Smith agreed and Emenkepali paid for a $600 plane ticket. But the quarterback didn’t appear and this infuriated Emenkepali, who confronted Smith.

He demanded that Smith give him back the money for the ticket. Remember, it wasn’t a huge amount of money for an NFL player but it’s about the principle. Smith refused to repay him and Emenkepali saw red. He punched Smith in the face and broke his jaw. That’s not the best solution and the pair became bitter enemies (via USA Today Sports).