The Packer-Seahawk game was a very important game, because if the Packers won, they would have a 2-game lead on Seattle plus the tiebreaker for homefield advantage in the playoffs.
Up 10-3 at the end of the half, the Packers had the ball on the Seattle 1, and on second down, a blatant pass-interference in the endzone that lasted a number of seconds was not called, and then another pass interference in the endzone wasn’t called on third down. Instead of the Packers getting a TD at the end of the half, going up 17-3, and having momentum, they had to kick a FG, Seattle got the momentum from holding them, and Seattle scored TDs on their first two second-half possessions to go up 17-13.
Another reason the Packers needed the TD at the end of the half is because of all the injuries on offense they had in the first half–Lacy, Adams, Bulaga.
After the first TD, the Packers needed to regain momentum, which for the Packers means throwing on first down, but McCarthy ran on first down for 2, punted, and Seattle scored another TD.
McCarthy was conservative in the first half, as usual, resulting in the Packers only scoring 13 points. McCarthy kicked a FG from 1-1/2 yards away at the end of the half, and being passive carried over to the defense, allowing Seattle to score TDs on its first two second-half possessions.
The Packers, down 17-16 due to the conservative play calling (running), got the ball back in the last minute of the third quarter. They ran on first down for no gain, then had a false start (once again a first-down run resulted in something negative), and the quarter ended with the Packers having 2nd-and-15. When the 4th quarter started, they then passed on the next 10 plays (one was a scramble on a called pass), and scored an easy TD. They didn’t have a running back in the game for those plays, meaning there was no threat of play-action and the Seahawks knew they were going to pass, but the Packers still scored an easy TD. Had McCarthy been aggressive all game, the game isn’t close. He keeps opposing teams in games, and when you do that, a turnover, an injury, a fluke play, etc. can cost you the game.