In chess we must to be carefull in each situation, also when the game is almost won or nearly lost. The danger is always around the corner.
I'm agree with Aagard when he says , in his books , that we must play like humans and don't like machines. The man can't be perfect.
I played a game in Chesslogger's online tournament in which I had lost immediatly some pieces and I was about to resign.
At move 19 I thought that my last chance for win this game was winning the queen and for this reason I played Qa5, I hoped Bc3.
My opponent doesn't see Qxa5 but plays c3 , and I arrive in this position.
I use the same idea of first.
It's clear that can't always be successful this strategy, but the black had nothing to lose!
I think that desperate positions require desperate choices !