6. ron rivera
The Panthers actually beat the Texans 16-10 in Week 4 and the Houston sports world was coming to an end. Rivera looked like he was rallying Carolina around backup quarterback Kyle Allen as starter Cam Newton was lost for the season. The Panthers were 5-3 with a backup quarterback by the halfway point, but they never won another game and Rivera was fired when the team dropped to 5-7.
Fun fact: Rivera is now in Washington, the last team he coached against before getting fired.