Perhaps the real benefit of sports may fall into the way that one team can play the role of hero to some while at the same time play the role of the villain, and that over time those roles can reverse even if the team itself doesn't change that much.
The same structure can be used to tell a story over and over, with the same cast of characters, but with vastly different stories. And those who like it will never tire of it as long as the structure does not change drastically from what it was when they came to like it.
And it doesn't have to make logical sense.
A few years ago, in the 2007 season, the New England Patriots won all their regular season games. Not only did they win those games, often they remorselessly obliterated the other team, running up the score late in the game when they already had a ridiculously comfortable lead. The methodical decimation was impressive, certainly, but when they got to the Super Bowl (against the relative upstart New York Giants) it was difficult to root for them to complete their "perfect" season; the way they'd played to get to that point had not demonstrated a level of… sportsmanship, I suppose… to make someone who was not a fan choose to root for them. Also, as the overwhelming favorite in the big game, they lacked the underdog vote.
I watched the game at a Super Bowl party, where no one was really a fan of either team, and where most people were not hardcore NFL followers. Also, generally at such events the game is merely the excuse to get one's friends over to hang out while vaguely paying attention to the game. However, as the game went on, I found myself pulling for the Giants without realizing ahead of time how much I would get into the game. It helped that it turned out to be a very entertaining game (even for the casual viewer) with a late comeback by the Giants to pull out victory. And even to this day, the sight of Giants' quarterback Eli Manning hoisting the Lombardi Trophy after the game provides a bit of joy that must stem from our affinity for David over Goliath tales, where the arrogant is taken down a peg.
The Patriots have not made it back to the Super Bowl since then, and although they have made it to the playoffs (indicating they've remained a strong team) they have not been the powerhouse they were that season.
This year, with three games left to go, they are tied for the best record in the league (with only two losses), and they are defeating teams who are likely to make it into the playoffs themselves in convincing victories. However, this season they're achieving this in a way that (from the highlights I catch) seems at least vaguely admirable; I find myself unbothered by their success—not that I'm rooting for them, but that I'm not having that subconscious reaction of quasi-revulsion. Maybe these last few seasons of not even getting to the Super Bowl has imbued them with a bit of hunger and humility (not in actuality but in my casual perception) that allows for them to be successful again without seeming deserving of a comeuppance.
Were they to end up in the big game again, depending on who they faced and the larger circumstances, there's at least the possibility they could have my tepid support, even if they're favored.
But we'll see.
It could be we have another inclination toward the flipside of the David-Goliath tale: the humbling and redemption (of sorts). To the extent it applies.
Life is nothing but a series of building our heroes up then tearing them down then building them back up, and at present—although neither Bill Belichik nor Tom Brady would be on a list of my "heroes"—they and their cohorts from Foxboro have escaped the villain list (although it's doubtful in any grand sense they deserve that, but it's not like this larger process is logical).
I don't mean to imply there's intrinsic evidence that there's other aspects of our minds that operate in some logical manner; never would I attempt to prove that argument.
Illogical thought is almost certainly what keeps life interesting.
This season I'm too busy finding not-entirely-justified glee in seeing "America's team" flop and ensure they won't even have the possibility of playing in the post-season (and become the first team to play in their home stadium in the ultimate game).
The teams from last season's big game—the Saints and the Colts—have had the good fortune not to have had the same level of good fortune on the field that they did last year. The Colts have been really humbled, and may not even make the playoffs if they don't pull out some victories in these closing weeks. Not their plan, I'm sure, but almost certainly keeping the need to see them dragged down at bay.
Many fans wish their team had this problem, I'm sure.