I honestly don't get why some people join LFMs.
Yesterday I was with a group running a chain. After the first quest, the leader asked if anyone wanted to do the second. I said that I was game if we were doing it together, but if the guy who raced ahead of everyone in the first quest was going to do it again, I was out. Leader agreed we would do it together. The racer piped in and said he would solo part of the second quest, to which the leader and I both responded that we did not want him to do that.
Sure enough, we get into the second quest and the guy is off to the races again, ignoring everyone else's wishes. Even better, the quest was Blockade Buster -- the guy was a sorc, and he decided to set off the self-destruct timer on the first ship, with a one-minute countdown, and without unlocking the hatches. He announces this on party chat after he's done it, and then says he's going "AFK". There wasn't even a minute left at this point, and half the party was somewhere else and going "???" -- I managed to get off the ship in time, while three others didn't. And the kicker? The party leader was a rogue, so there wasn't any need for the timed detonation anyway.
Why do people like this even join LFMs? I seriously don't get it. I join LFMs for two reasons: because I don't think I can solo something effectively, or because I want the company and find doing the quest as a team more fun. What is the point of behaving as this guy did? He obviously had no interest in actually working with the party, and if he was just in a hurry and was so uber that he didn't need us, why not just solo it, which would be easier anyway due to less scaling?
Maybe he was just trying to impress us. He did, but not the way he anticipated, which maybe he figured out after we recalled and regrouped without him (though I doubt it).