- Whining and complaining about how your faction and everyone in it is a noob.
- Getting depressed about how you lose all the time
- Belittling other players for not being perfect.
The whole idea of a team is that its members cooperate with one another, and cooperative language is generally a lot more productive in any case: "Hey, I appreciate your healing in here. Next time I'm carrying the flag, though, could you and I team up with you focusing on healing me in particular? Thanks!" Some people can't take any suggestion or advice whatsoever, but chances are that the healer actually wants to cooperate and help his or her team succeed. They just even be happy to accept a polite request. And if not, spewing all manner of insults just makes the insulter look like the bigger idiot anyway.
If a few readers here are the type of people who like to belittle other people in battlegrounds, they're probably just going to flame me for writing this in the first place. That's what belittlers do, after all, is belittle people. But for the rest of us out there, who value teamwork and civility in our social groupings, it may help a lot, if you are willing, to stand up for the healers, or whoever on your team is being unfairly insulted. Some of them are used to it, of course, and just let such insults wash over them like water; but others will be pretty hurt by such insults, and may really appreciate your putting in a good word for them, even if they don't say anything at the time. You don't have to take all that bigotry the other person is spewing onto yourself, though -- if it gets real bad, you can refuse to talk about it anymore, or even just ignore them. At times like this even a game isn't really about having fun anymore -- flamers ruin that fun pretty nicely on their own -- it's about doing what's right to the extent that you can, the same way you would in real life.