It shouldn't be a surprise, but the Green Bay Packers' biggest weakness all season long is what ended up costing them in the playoffs. I'm, of course, referring to the special teams unit.
Basically, pick any aspect of special teams play, and in all likelihood, something went wrong at some point this season. In short, there were muffed punt returns, poor blocking, penalties, bad snaps, questionable holds, shanked punts, missed field goals, an ineffective kick return unit, and Green Bay was the only team to allow a punt return this season, among many other problems.
You get the idea, and you saw it with your own eyes--it was rough, to put it mildly.