I send love mail occasionally such as "gg" or "nice [character.]" I eked out a victory against someone yesterday who was a real beast with Jade. I sent him a message saying "nice jade" and he responded with, "Thanks dude, but your cage was better gg." That made my afternoon.
Another time I won a close match with a guy and we rematched. I switched characters and this time I was totally wrecking him. He quits before the first round is over. I thought, "Oh well, that first match was fun." I start to type a "gg" message when I receive one from him that said, "now u spam?" So I edited my message-in-progress to say "whatever quitter." I generally don't talk trash but I will ruthlessly taunt rage quitters.