In WoW I usually think there are two kind of players; those who want and those who don't want. And before I explain what I mean by that I'll say that I don't usually ever think anything is black or white, and there are always extremes and/or uniqueness in any field, even WoW. But still, most players can be categorized into two different types. I've been both. And I don't think you have to be one or the other to enjoy the game more. Only you can say how to play your game. But WoW is still a MMORPG. The first M stands for Multi for a reason. You play with other people so in some cases it will be needed for you to do more stuff than you want to in order to do other stuff you want to, aka compromise. Kinda like working to being able to afford playing WoW. I'll explain.
Those who want - the striver
Some players see every pve or pvp encounter as a chance to learn something new. Some people try to dig every piece of information there is about something so that they can finish their own puzzle about what is good and what is bad. Some people look at their own effort and think; "what can I change to make things work even better?". Some look at their failures and think; "what can I do better?". "I" being the emphasized word here. Some people strive towards perfection. Perhaps not in everything they do, but in some area they have chosen for themselves. That is how they enjoy what they are doing. That is how they keep on enjoying it, by getting the feeling of learning something, implementing it and seeing that it works. As a sort of scientist, testing a theory, devising it into being as good as possible in every situation. To them WoW is a hobby.
Those who don't want - the content
Some players go with what works. Some people think there is no need to change a winning recipe. They can ask "what is the best way to do this?" but not wonder why. They accept that things work in a special way and go by it, but don't care much about putting time into going beyond what works. They look at their own effort and think "this works ok". They look at their failures and think "better luck next time, someone will make it work". They don't get that special kick out of feeling they contributed to the whole. All they want is to enjoy a moment of playing the game their way. They enjoy it more by knowing they can play it the way they like to. The game is a passed time, away from the boring "musts" and "needs" of the outside world. To them WoW is a way to spend some time doing something not boring, sorta like watching TV.
Both these ways of playing the game are good. And like I said I've been both. The problem is sometimes these two types clash and don't work well together. Blizzard has tried to do parts of the game that will keep both sides happy for a long time. It is clear though that some parts work better for the one type, and other parts for the other type. The content type, also sometimes referred to as "casual" which I think can be somewhat confusing at times, is ok with just logging on, doing some heroics and be done for the day. Or maybe level yet another alt just to be able to log on and do some quests. The striver however, usually puts all his effort into one char. That way it'll be easier to learn everything there is to learn about that particular class. They usually don't like questing (unless it's for achis) or doing heroics (unless you pull the whole instance in one go). They need challenge. The content type doesn't want much challenge, they want relatively easy rewards relatively fast. They don't have all that time to spend, or they simply don't want to spend it.
Raids is better for the striver. Especially new content. And this is where the most friction will arise, unless you've got an elitist guild who only invites strivers. The problem is you can't be too content and expect success in raid. Blizzard has actually designed most new raid encounters (not counting Naxx) to demand that you put some effort into your char, other than just passed time amusement. The first bosses of the raids in Wotlk so far have been easy enough to bring some passed time players. But the harder encounters, or the hard modes don't usually allow for those kind of players. They put a strain on the rest of the group, to put it mildly.
Why am I bringing this up? Because some people don't realize that their playstyle doesn't work in the entire game. There will be parts of the game where you have to realize that you will have to adapt to the needs of the rest of the group. This goes both ways of course. The striver who wants to kick anyone from a heroic who doesn't display more than 7k dmg will probably not get to do many heroics a day (unless he is tank perhaps). But some things are needed not because the players demand them, but because the game does. No one can tell anyone how to play the game, be it content-style or striver-style. But they can tell you that your way of playing doesn't work for a particular part of the game. Then either accept it and back down, or change if you really want to experience that part of the game.