Why is it that Roger Federer doesn't play that crisply in the opening rounds at some tournaments, and then at Wimbledon plays like a god? I would have thought it's because it's grass, but he certainly wasn't invincible at Halle. I suppose the counter-argument would be that Federer just came back from clay, but that wouldn't explain why he played so many 3 setters for the entire tournament. Does he just decide when to turn on the godly switch? One could also say that it's just by chance, yet how has he done it for almost four straight years at the same tournament? Why can't he just play like that all the time on the faster surfaces where he excels?