Kansas City Chiefs – 2016
Patrick Mahomes has done a good job of helping Chiefs fans forget about their previous 50 years of woe. But the franchise put them through tough times and broke their hearts every season. One of the worst in recent memory saw them suffer a miserable defeat against the Steelers (via SBNation).

There are a couple of reasons why this one-and-done divisional round loss was heartbreaking. First, it meant that Kansas City fell to 1-9 in their last 10 playoff games. Meanwhile, the AFC West winners became the first team to lose a postseason game despite scoring two more touchdowns than their opponents.