He loses concentration when he gets frustrated. If he cuts this out he's golden.
Take that sh*t show of a game on Tuesday. He was getting wound up by the obvious one-sided officiating, and when he lost the ball (unfairly in his mind) he let his frustration show. He could have chased back, but knowing that c*nt of a referee the chances are he'd have given away a free kick in a much worse position. Also, he must have considered that the defenders (5 of them) would have been able to deal with the situation.