Is his attitude. He has no "fight" in him. Anytime anyone, from Rafa, to Monfils to Djokovic, takes a lead against him, his entire body language changes incredibly to show how disgusted he is, and not in a good way. His body language conveys disgust with his own play and also in a perverse sort of way, that he doesn't respect his opponent's play because he just looks like he gives up. This only encourages his opponent to try to "finish" him off and gives them more confidence. When you look at Rafa, you see that he remains focused on how to outplay/outlast his opponent regardless of whether he's winning or losing. Have to say, even though I'm a Federer fan, and as beautiful as Fed's game is (or was, to be fair), I really don't like his attitude. He generally says the right things to the press for the sake of sportsmanship, but he definitely has this sense of arrogance about him that, I think, is detrimental to his ability to defeat opponents right now. And I don't see it changing. I think there's a 50/50 chance that he'll never win a GS again. Alright, I think he'll win at least one more, but after that, it's 50/50 whether he'll ever win another one unless he has a change of attitude.