Euripides from Critical QQ made a post the other day about why he raids, also touching on things that he doesn't care about while raiding, such as story: If Kael’thas had instead been a featureless blue cube named “Final Boss” and had abilities called “Phase One Ability” and “Phase Two Ability”, the fight would have been exactly the same to me. This surprised me quite a bit, even more so when Larísa pretty much agreed, the reason for my surprise being that I can't agree with this sentiment at all and that I couldn't even imagine so many people feeling this way. It did make me think about why I raid though, and I basically came up with four different reasons.
The first one, if we go alphabetically, is what I would call adventure. This is exactly the bit that Euripides and Larísa say they don't really care about. They talk about it purely in terms of lore, but I think that doesn't quite cover it. I mean, I don't need to know all of Onyxia's background story to appreciate the excitement of my little troll facing off against a huge, fire-breathing dragon. It still wouldn't be the same if she was just a red cube.
I may not be hugely into roleplaying, but I would have thought that most WoW players care at least a little bit about immersion and becoming part of a big fantasy world while they play. I mean, would you really keep playing if it was all just shapes and colours with no context? I know I wouldn't, and that's still true when I raid. I'm not massively concerned with the backstory of the characters I fight, but I love me some good voice-acting, epic cut scenes (hello there, Kael'thas phase three) and the like. It's like watching a good film, only more interactive.
The second reason to raid would be the one Euripides lists as his main motivation, gaming: solving the puzzles, overcoming the challenge, beating the game. This is one aspect that isn't actually all that important to me if I'm being honest. I'm not really impressed if a boss is a complete pushover that poses no challenge at all (I'm looking at you, normal-mode Jaraxxus), but really, most of the stuff in WoW is pretty easy if we're being honest - I enjoy it anyway and don't expect raiding to be vastly different.
My third reason to raid (still going alphabetically) would be progress. This isn't so much about how raiding appeals to me personally, but about how it benefits my character. There are a lot of achievements that you can only get by raiding, so if you want to max out your achievement points you'll have to raid. The same is true for gear really; while you can get very good gear just from farming emblems these days, if you want to be decked out in the best stuff available you'll still have to raid. That's a pretty solid reason to do it regardless of how you feel about the activity itself; it helps you to make the most of your character.
And last but not least for me, there is socialising. I actually think that this is one of the most important reasons for me to raid, if not the most important one. It's not really the first thing that comes to my mind when I think of raiding, but if I imagine raiding with a bunch of strangers instead of my friends I find the thought very unappealing, so it obviously matters.
From this point of view raiding isn't really that important as an activity of its own, but it serves as something to bring people together, as an excuse so to speak, so you don't "just" sit there and talk. People go out for a drink together, go bowling with friends and the like for pretty much the same reason. The shared activity gives you something to talk about if there's nothing else, and actually engaging in it nicely fills any gaps in the conversation.
There are quite a lot of people that I like in my guild, but in all honesty I don't think I could ever make the time to do things like quest, instance etc. with all of them individually. Raiding handily brings us all together and lets us enjoy each other's company three nights a week anyway.