I think Brady and maybe some others put too much pressure on themselves to win it for Kraft's deceased wife. Reminded me of Bills a little before loss to Redskins in their 2nd SB appearance. Kelly & Co. were tight as drums kept saying "we have to win, have to win."
Again you can pee and moan all day about this and that on both sides, and the ball not being round, but at end of the day one team scored 4 more points that the other.
The only time I see it as acceptable is when the refs play too much a hand in the outcome. I don't think that happened today.