Federer cheats by breaking the opponents momentum. If he's losing he'll find a way to stop the match. There are numerous examples of this, but I guess you don't see them.
For example, I was just watching Shanghai, 2012, Federer against Murray. Murray wins the first set and is hitting Fed off the court. Murray wins the first set.
At the beginning of the second set Fed is serving for 1-0. Try as he might, he can't win the game point. It goes to 5, 6,7 deuces.
Then, the rain begins to spit. It's not coming down hard, it's barely coming down. Federer wants to get off the court. The umpire says it's not bad. You need to play.
But Federer doesn't want to play. He follows the umpire to the chair still pleading his case. The ump repeatedly tells him the rain isn't a rain, but they're in the process of closing the roof anyway.
Still, not good enough for Roger. He continues to plead his case.
I quit watching it after that because it was so disgusting. This wasn't like RG 12 where it was raining so hard that it was affecting the courts. It wasn't even a drizzle.
I had to turn it off, because it reminded me of how Stan was kicking his butt and all of a sudden he found reason to argue with the chair. Arguing for so long that when play resumed, Stan was a nervous wreck and out of intimidation, weakly folded.
Then, remembrances of the famous bathroom break with Davydenko where he went to the restroom to wait for the sun to go down.
Seriously, you should be the last one to talk about cheating and unsportsmanlike behavior, because you would see if you weren't so blind.