Chess is a hard game after all

One of my favourite sayings is "Chess is an easy game, it is just hard to do the easy things well". However one thing that people are now discussing from the current Linares tournament are the number of blunders, blunders that people normally don't expect from the top players. So much so that Chessvibes is even running a poll about what the cause could be. Of the number of choices I'm pleased to see that "These aren't blunders, these are highly complex choices" has the most votes, as at least a large group of fans recognise that chess isn't always easy.
One game the is being used as evidence is the Carlsen v Topalov game from Rd 12 where Topalov plays a howler on move 34 and walks into a mate.

Carlsen,M (2733) - Topalov,V (2780) [A28]
XXV SuperGM Morelia/Linares MEX/ESP (12), 04.03.2008

1.c4 e5 2.Nc3 Nf6 3.Nf3 Nc6 4.d3 d5 5.cxd5 Nxd5 6.e4 Nb6 7.Be2 Be7 8.0-0 0-0 9.a4 Be6 10.Be3 Nd7 11.d4 exd4 12.Nxd4 Nxd4 13.Qxd4 c6 14.a5 Nc5 15.Qe5 Nb3 16.Ra4 Bd6 17.Qh5 g6 18.Qh6 Be5 19.Bg5 Qc7 20.Be3 Nxa5 21.f4 Bg7 22.Qh4 Bb3 23.Rd4 Rad8 24.e5 Rxd4 25.Bxd4 c5 26.Be3 f6 27.Nb5 Qd8 28.f5 fxe5 29.Bg5 Qb6 30.f6 c4+ 31.Kh1 Qxb5 32.fxg7 Rxf1+ 33.Bxf1 Kxg7 34.Bd8 (D)
34... Nc6 35.Qf6+ Kg8 36.Qe6+ Kf8 37.Bg5 1-0