I never respond to abuse.
Was playing in a Poker Stars
freeroll, top 100 to qualify for next round, and this idiot was being very aggressive with both his chatting and betting.
I got a free look at the flop (from BB) with a suited 2s 5s. The flop was As 4h Js. My stack was about 8000 and his about 5000. He goes all-in (as he had done every two or three hands since I had been moved to the table) and I call. He was bluffing and had nothing. The turn did not help, but the river was a 3, completing my straight.
Well did he sound off, and abused me until the game finished. He was also back, for about half an hour, abusing me in the weekly final four days later.
I found it rather amusing that someone could get so worked up over a freeroll.