12. Bob Sutton
The Kansas City Chiefs won their first Super Bowl in 50 years in 2020. But one man arguably prevented them from winning the trophy one season earlier. That was defensive coordinator Sutton, who tarnished his reputation throughout the campaign. The Chiefs made the AFC Championship game in 2019 but lost to the Patriots. While the Pats definitely received some favorable decisions from the officials, the Chiefs let themselves down on the day as well.
Defensively, they were their own worst enemies. Patrick Mahomes was sensational but there was only so much that he could do with that defense behind them. They yielded 13 New England third-down conversions, which was frankly unacceptable. The most damning indictment of Sutton’s abilities at the highest level was the fact that Kansas won a Super Bowl almost immediately after they fired him.