Murray - Constant swearing, mug.
Rafa - Rosol bump, badeye / glaring at opponents, occasional swearing in Spanish, time wasting, gamesmanship
Nole - time wasting, gamesmanship
Federer - rare swearing USO'09 and AO'13, arrogance
Who's the worst?
The one you hate most.
First off, I don't "hate" any of them, but in terms of gamesmanship/what you are referring to I'd have to give it to Nadal. He plays extremely slow, he hits extra hard during the warm-up (for intimidation), and tends to pick crucial times for trainer/bathroom break.
What is frustrating is that he DOESN'T need to. He's so good and so talented I wish he would drop the act and just play.