2 years ago, a lot of people thought the Cardinals didn't "deserve" to be in the playoffs because they had the worst record of all the playoff teams, worse than other "more deserving teams" that didn't make the playoffs. They then beat every "better" team on their way to the Superbowl, and nearly won that.
I believe a few years before that, the Stealers had a poor record going into the playoffs, and most people were "certain" they'd be one and out. Instead, they beat all the "better" teams on their way to a Superbowl win.
It just goes to prove that anything can happen in the playoffs; and every team that makes it into the playoffs, has earned it.