I've said it in many posts before, and I'll mention it again: I tend to mimic what the other person does usually. Long as they're respectful I will be as well. I don't taunt if they don't. They start taunting, tea-bagging, whatever then I will gladly do the same.
I just don't see the need to be respectful to someone who obviously chooses not to be respectful themselves. I want to enjoy the game and be able to have fun. There's really no need to ruin it for everyone else, especially considering the fact that new players along with young kids go online to play and just have fun, maybe even improve. They don't need to be belittled for their efforts.
Now, I have created some responses to salty tags and only use them when the situation truly calls for it. I never do it unprovoked.
As in if someone chooses to continually throw salty tags out and continue to make themselves look like rude idiots. My favorite ones to use is simply "LOL" and "K", especially "K". Throwing that out for every salty tag seems to make the other side twice as salty sometimes. It's great. I also have "InSALTed?" and "NaCl" to respond with. I'd rather not use these at all, but hey... Sometimes the other side needs to take their own medicine and it's often funny to see them seethe with rage because they can't take what they dish out to others.
In short simply be respectful and you'll get it back, otherwise expect the same rudeness back that you dish out.
