Quality of relievers. Without question.
2012, and I'm sure some kind of unique stat will come out concerning this, was a historically bad year for bullpens. Years ago, even recently, when a game went into the 7th or beyond with a decisive lead, it was over. Period. This year, though? A game was literally not over until the final out was recorded. So, so, so many bullpen breakdowns this year that it was absolutely of historic proportions.
