In my native language they say:
A L' E' INUTIL INSEGNA' AL MUS, SI PIART TIMP E IN PLUI SI INFASTIDIS LA BESTIE!!
(translated) There is no gain in teaching the donkey, you waste your time and annoy the beast
I'd enjoy watching Safina, Wickmayer, and Larcher de Brito a lot more if their grunts didn't bother me so much, but whatever. It's tennis, they grunt. If I wanna watch a match they're in badly enough, their grunts aren't gonna stop me.