5. Chip Kelly
Kelly made a number of horrendous decisions while in charge of the Philadelphia Eagles that still bemuse today. His first two seasons finished with winning records but the third ended 6-9. Bizarrely, he approved the trade All-Pro LeSean McCoy to the Buffalo Bills. Yes, the same Bills who were their divisional rivals. The loss of Nick Foles and Jeremy Mclin also had a negative impact on their fortunes.

The Eagles fired him but he had another shot in the NFL. Kelly managed to run the San Francisco 49ers into the ground too. After beating the Rams in their opening game of the season, they went on a 13-game losing streak. At least he was consistent. But finally, the 49ers had enough and cut him loose at the end of the season.