It seems to me that Federer pulls out his very best tennis at critical junctures of losing a match. He seems to coast along at 70% then puts on the burners when in trouble. The problem is that he turns on the burner a bit too late for comfort sometmies, and this could cost him in big matches. Then sometimes Fed seems to "play around" when he's really ahead, a sign of boredom. Example, in the final set against Baghdatis, it looked like Fed was tanking some shots, including a couple of silly drop shots, and a bunch of missed first serves.