This is the problem with MMOs.
If you aren't playing with friends and are unsure of what you're doing it actually makes YOU the douche, not them. Will you listen if I explain why?
When you join a group and it's 2, 4, 9, 14 or 24 other strangers that you're grouped with they are all depending on you and counting on you to perform well. If you don't perform well you literally (yes, literally) waste the real life time of those 2, 4, 9, 14 or 24 strangers.
Now, this isn't your fault. You're just playing a video game and you're trying to have fun. It isn't their fault either because they are just wanting to spend their RL time playing a video game and have fun. It's just the unfortunate nature of an MMO that groups strangers together randomly.
Think about it from a different angle for a second. Let's say you went and signed up for a community baseball team with other young adults. If you didn't know the first thing about how to play baseball and you didn't bother to practice or read the rule book you would be wasting the time of the other guys that showed up to play. You could be new, but you would at least practice and read up on it so you didn't ruin their evening for an hour or two each week.
That's what LFG is in WOW.. Sucking the fun out because it let's other just trying to play and enjoy the game waste your RL time.