Is this just showing off?

According to Magnus Carlsen, he has managed to lose the 3rd round of the last 4 tournaments he has played in. I suspect it doesn't help if he decides that he needs to sacrifice a piece on move 10 in a reasonably familiar opening system. It does not even qualify as a 'coffee house sac', as 2 pawns and a check is the usual rate of exchange for such sacrifices.
Having said that he almost pulled off a win. By move 30 Carlsen had collected enough pawns to give him chances to save the game, as Naiditsch let the position slip away. Past the first time control, Carlsen was even, and a few moves later he began to develop serious winning chances. But on move 50 he made his last big mistake, and Naiditsch had enough to win the game.
While I am a little surprised with Carlsen losing towards the end of a long game it can possibly be explained in terms of what usually happens to Carlsen's opponents. Being forced to find the best move just to stay in the game is hard work and the longer you have to do it for, the tougher it becomes. Possibly the effort in playing 'catch up' chess was what did Carlsen in, and if so, the sacrifice was unsound on more than one level.

Naiditsch,Arkadij (2706) - Carlsen,Magnus (2865)
GRENKE Chess Classic 2015 chess24.com (3), 04.02.2015