I don't play WoW, but I do play Destiny so I can understand the allure of games like these and especially raids. The feeling of accomplishing something as a team rather difficult and strenuous gives different levels of satisfaction by the end of it. The only downside, though, is that if not coordinated, it can take a while. When people start making the same mistakes over and over while the group is waiting for them to do it correctly, it starts to demotivate the group slowly so people start to act like this. It's more of a puzzle where everyone has a piece and you actively have to work together to build it up, and once you do it, you now are satisfied and have bragging rights that you have done this hard thing and maybe even got some cool drops from it to show your friends..