what's wrong with 'sup'?

You know 'sup' is a form of greeting in New Zealand. It means "what is up" as in, ow are you and what have you done in the past short while. You saying hello means nothing except to let everyone know that you're here and you want them to reply back :)

er.. that's "how are you" not "ow are you"

Trust me, there are plenty of healers who are incredibly rude and irritating, maybe even more than dps, sad to say. But as for the running before you're zoned in, no buffing, and no waiting for mana stuff, I'll agree with you that those kinds of tanks are a pain. But the mr diva thing does seem to happen to tanks more than the others. I'll admit that I've had it happen to me. It's something about being in a position to save the group the most that makes it so, and it's not something that a lot of tanks will notice, although those that do try to catch themselves, since the smarter ones realize it's still a team, and they can be replaced.

As for the replying to "sup" and such.... what exactly is your issue here? Seriously, I don't get the problem. It's just an expression, and it's far less annoying than some that have become common.

As for your question of if LFD is good or not, I'm almost leaning towards no, due to the you can't earn friends with it unless you're really lucky, and for whatever reason I almost never get paired with people from my server. (Wyrmrest Accord)

I like 'sup, actually, i imagine the person is relaxed and friendly, but that's just me.

Eh, my reaction to 'sup' is just me being my normal cranky self. Pay it no mind.

I really hate it when tanks do that too. Several times I've entered an instance after questing in shadow spec and write "I need to respec and get mana" only to have the tank start pulling and leaving the group if he/she dies. Some tanks just seem to be in such a hurry when instances start.

I don't see why sup would make a person seem foolish. It's just like saying bye instead of saying god be with you when you part ways. I guess asking someone what's up with them or perhaps upcoming when you just mean to greet them is a bit odd though but it's a common way of doing so.