Mike Matasow from the WSOP -
Don't try that [BEEP] in my pots. I'll [BEEP]n take you down every time. I have great big [BEEP] and you have little tiny [BEEP]. My [BEEP] are huge and yours are [BEEP]n itty bitty.

Sometimes you can't avoid a mouthy player. But you are 10 times more likely to come across a mouthy player online than you are in a live game.

Online - just block chat from that person or everyone if you want. Live, ignore it. Either way the most important thing is not to let it affect your game.