If you have played WoW for more than five minutes, you have done a quest. It is nearly impossible to avoid doing them altogether. Since the option has been implemented to have instant quest text and the options tracked on the map by Blizzard's default UI now, most players see the exclamation mark, click on the NPC, accept the quest, and go get the items -- whether it be someone's head, 10 rocks, or going to kill a certain number of creatures -- without paying attention to the why. We want the gold, experience, achievement, or perhaps a quest reward, but we cannot be bothered with why we need to commit genocide on a population of wild animals. We would rather crit the mobs required for the quest than be crit by a wall of text.
I am as guilty of this as the next person: Oh, bring you murloc eyes ... Sure, why not? Kill a bunch of boars? Whatever. However, when I recently went back and finished off Loremaster, I found myself actually paying attention to some of the quests, and I realized there can be some great stories there. The Burning Crusade, Wrath, and soon Cataclysm have come a long way in terms of making the quests feel like they are leading somewhere, as opposed to killing these random mobs for no apparent reason. While working on Loremaster, I was like, "Wow, that was a neat little storyline in that quest chain!" It made me both impressed and a little sad, wondering about all the possible nuggets of story I had simply ignored just so I could level a couple of minutes sooner.
Do you actually read the quest text? Do you ever want to know why we have to kill the creatures we kill and why the NPCs want these seemingly inane items? Or do you just do it for the XP and money and could not care less?