The Pittsburgh Steelers went 15-1 in 2004 and reached the conference finals. They won the Super Bowl the following year in 2005, and then won again in 2008. Even though there were some down years in between, with non-playoff seasons in 2006 and 2009, they were back in the big game in 2010. And they lost, to the Green Bay Packers and Aaron Rodgers.
And that was so much more than just a loss, for the Steelers and head coach Mike Tomlin. It was more than just a loss in the Super Bowl, as well. For a team with that recent resume, with the players on that roster, it was a pivot point that went the wrong way, as Tomlin reflected on during his appearance on The Pivot podcast with Ryan Clark, Fred Taylor, and Channing Crowder.