I'm not sure if you believe in curses but it's a great way to explain unexplainable streaks of suckiness (technical term). There are some teams who have been bad for so long, or have had so many unfortunate things happen to them that you're just sure they're cursed.
Last January would have been a great example. The Kansas City Chiefs hold a 28-point lead in the third quarter of a playoff game. What's the worst that could happen? You know the worst that could happen.
You have the Bills. Losers of four straight Super Bowls, something no one has come close to repeating. They haven't won a playoff game since 1995. Drew Bledsoe was their quarterback the last time they had a winning record (2004). They just lost their young, star linebacker in Kiko Alonso to a torn ACL at a time when optimism was rising. Brian who runs Buffalo Rumblings would surely argue the Bills are the most cursed team in the league.
But what about the Browns? They have become a punchline in the league at this point. They have made the playoffs twice since 1989, even worse than the Chiefs. Quarterbacks go there to die, including Brady Quinn, who was my guy in 2007. Speaking of 2007, they won 10 games that year but still couldn't qualify for the playoffs. They once fired Bill Belichick.
Yes, the Chiefs are included here. They're as cursed as anyone in the league right now with 20+ years without a playoff win. If the Chiefs aren't cursed, how do you explain losing that 28-point lead last January? How do you explain three young players all tearing their ACLs in a matter of weeks in a year the Chiefs are supposed to be contending? How do you explain the inability to make Peyton Manning punt just one damn time? The ref inaccurately calling Tony G. out of bounds vs. the Broncs in 1998? How does a non-cursed team make the decision to hire Gunther Cunningham as head coach? There's just no explanation for it (only partially joking).
The thing about the Chiefs is that they have had quite a bit more regular season success than the Browns or Bills in the last 20 years. That means their failures have been more meaningful because more was at stake. But it's impossible to have more big stage failures than the Bills, who lost four consecutive Super Bowls.
My curse rankings look like this: 1.) Bills 2.) Browns 3.) Chiefs.
Update: Readers point out the Lions should be included here and they're right.