Buffalo Bills
Sean McDermott is on course to become the Bills’ greatest coach ever. As Buffalo became a bonafide contender, he transformed Josh Allen into one of the NFL’s leading quarterbacks. A Super Bowl win would be the icing on the cake yet that won’t be happening this year after their latest playoff exit loss to the Bengals. But McDermott deserves immense credit for making people take them seriously again.

Mike Mularkey is probably their worst coach of the past couple of decades. Mularkey took the reigns in 2004 and led them to a miserly 5-12 record. Incredibly, they had a shot at the postseason but Mularkey failed them. He lost a game against backups to end the Bills’ playoff dream for another year (via Sportsgrid).