As odd as it seems, the Packers' loss to the Chiefs is just what Green Bay needed. Sure, it would've been exciting to see a team go 19-0, but the fact that it has never happened shows just how difficult that is to accomplish, and Green Bay is in much better position to win a second consecutive Super Bowl after realizing they are still human after all.
No matter how much they may deny it, the players and coaches think about the possibility of going undefeated, probably on a regular basis. It would be an incredibly exhilarating feat to accomplish, but it would have been only the icing on top of a monstrous cake (the team's performance over the course of the season) if the Packers indeed win the Super Bowl.
The further an undefeated team advances without losing makes the "will they go 19-0" talk only more and more distracting, ultimately to the point that it's likely unhealthy for a team and makes it more difficult for them to focus on their larger goal of winning the Super Bowl. Nobody is perfect, and once a team realizes that, it eases the tension and immense pressure.
This is a needed reality check for the Packers. I'm not saying they're not as good as we thought, just that it reminds them that nobody is perfect. In fact, I believe they now are in prime position for a Super Bowl run. Nobody is unbeatable, but some teams are very hard to beat.
A one-loss Packers team, to me, is much scarier than an undefeated Packers team because the former will not have the immense burden of continuing their perfection and can play to win, while the latter will be faced more with the task of playing simply not to lose.
It will be interesting to see if Green Bay loses again before it makes the playoffs. Regardless, the path to Indy just got a lot less steep for Aaron Rodgers and company.