Most fun I ever had online shooters was Unreal on Wireplay. Everyone was respectful, complimented one another on shooting them in the head and got to know one another with time.

These days I don’t bother because everyone’s a jerk.

In some contexts competitive back-and-forth insulting is a baked in part of the culture, and is mutually enjoyable. You're only a jerk if you can see that the other person is no longer enjoying it and you continue anyway.

You cannot see the person you’re insulting in an online context so you cannot see if they are “no longer enjoying it”. Engaging in such behavior means you’re a jerk.

Trash talk is also not the same as engaging in trolling. Telling someone you’re going to kick their ass is perhaps reasonable trash talk in some cases. Calling someone racist or sexist epithets is not.

Even in text, it can be pretty clear when you've crossed the line and it's time to stop.

Please don't take my comments to mean that insulting/mean behavior is OK, though. IME many commenters across the web are far to quick to hurl insults in situations where they have no idea how they'll be received.

I was called racist, even in person. It was always for fun from both parts. So it might be ok, although in 99% of online "bad behavior" is actual bad behavior.

Yes I do enjoy it but it heavily depends on the game. In other games which has a more mature community I never trash talk.