You are there to learn and even to teach.
You are there to work together with four other people you may or may not even know. You are there to share knowledge, to help the group succeed, to learn skills you'll need later, and to help other people learn them. While some people will always have better reflexes than others, the general difficulty of even current heroics is not so great that a group cannot succeed even doing things with a brute force approach, trying to smash down every pull. What group coordination and information sharing can accomplish is to make it all much easier, take less mana on the part of your healer, and train everyone (including you, no matter who you are and what your role is) to do things more efficiently and with less downtime.
This goes for everyone. Tanks can learn to control pulls, mark CC and refrain from breaking it, and make sure healers are ready for pulling a new group. DPS can learn to use their CC and interrupts effectively and swap targets effectively without breaking CC. DPS can also learn when and how to use abilities to help give the tank a breather or rescue the healers. And healers can learn how to triage effectively, how to use CCs that they have and to explain to groups what their big AoE heals are and what they look like so players trained not to stand in things will stand in the good things.
Part of the problem
Modern heroics are designed to effectively cause a good group to reeducate its members. When game design changes, it's the players, not the designers, who do the work of teaching each other what to do. If you're not willing to learn (no matter how awesome you think you are) and not willing to teach, then you're not helping the group succeed. That's what it all comes down to.
If you think you're too good to do either one of these things, then don't queue. You're not helping. It doesn't matter how well geared you are, how long you've been playing, or how awesome your numbers are, if you decide to be a drag on the group by not listening to what others share with you or not sharing what you yourself know. If you're going to get impatient, slag everyone off and leave the group in a huff, you just wasted everyone's time, including your own.
Right now, we're all learning. We're all teaching. If you can do either of these, you can get through a PUG. It's that simple.
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