Quality trash-talk is best when it hovers right around the line of decency.
I'm insulted 10% of my wins, and 40% of my wins my opponent leave the clock running.
The reason they insult is because they have the wrong mentality. I play knowing that I am going to lose unless my opponent blunders and that I'm an idiot, retarded. So I enjoy the game, even if I lose.
I would say 95% of chess players only enjoy wins, ,if not more.