If you get a chance to watch the documentary The Raid, I can recommend watching it. It is not always pleasant, but realistic enough, and touches a lot of the issues and misconceptions about raiding. Also gives you the opportunity to watch a complete Icecrown raid, in case you never did one yourself.
What struck me most about film was how much it made raiding look like work. You have to be there at a specific time for a specific amount of hours, and you have to perform well during that time. Sounds a lot like my job.
What the film failed to show was how the guild involved got their raid team together, and who got excluded. No interviews with guild members who didn't get a raid spot or got kicked from the guild, although those undoubtedly exist. Succeeding involves synchronous excellence of execution, and that ends up being both the biggest strength and the biggest weakness of the system: Winning together leads to a strong team spirit to develop (shown in the film), but losing together risks people pointing fingers at whoever they perceive to have been the weak spot.
Real-world groups of friends often include people who aren't quite as bright or successful than the others. Raiding makes that difficult for groups of friends in virtual worlds. Selecting your friends by their gearscore and raid performance gives you greater virtual rewards than selecting them based on how nice they or, or sticking with them through thick and thin out of loyalty. I still hope that we will get some mainstream MMORPG one day which is about people working together without penalizing players for sticking with their under-performing friends. I think that would lead to greater social cohesion than the raid system.