In the NFL, the regular season doesn't mean much in the postseason. Generally, top-seeded teams don't always emerge victorious, much like the way top-seeded teams in, say, the NBA do.
And as a result, NFL teams that performed exceptionally in the regular season, and even had some postseason success in that same year, aren't guaranteed to play football in late January of early February.
Normally, the narrative of the NFL playoffs are dominated by these teams, though, as they begin their quest towards dominating teams much like they had in that respective season.
However, when these teams don't make it to a Super Bowl, or don't win a Super Bowl, in some cases, they're considered the team that should have and could have, but didn't, going down in NFL infamy.
And while there's a literally upwards of 50 teams who fit such a description, here are 25.