What Happened to the Mavericks?

I am curious, from a Mavericks' fans' perspective (or at least from somebody who has watched them a lot), why they lost in the first round of the playoffs. Was it Dirk? Was it Kidd? Caron Butler seemed to play well. Was it the Spurs defensive strategy? If you are not a fan of this team, but have watched them some or if you have special insight I am interested in your opinion. From an "X's and O's" standpoint, why didn't the succeed?