537 Worries of Happiness

The NFL has become the top-rated television program on the North American continent year after year, not only because of the vast fan base for football but more importantly because of the suspense.

Thanks to the existence of a hard salary cap, it's difficult for teams to assemble a group of top-tier players to charge for a championship, which narrows the gap between strong and weak teams. Coupled with the intricacies of team strategy, the suspense has skyrocketed, leading to countless possibilities for playoff spots and championship contests every year.

It's for this reason that the casual onlookers and passersby don't hesitate to pay attention.

In the half-century history of the Super Bowl, only seven teams—Green Bay Packers, Miami Dolphins, Pittsburgh Steelers, San Francisco 49ers, Dallas Cowboys, Denver Broncos, and New England Patriots—have succeeded in defending their championship.