The thing with MMOs is, other people's behavior and oftentimes skill directly relate to your ability to have fun if progressing and getting things done is fun to you.

When you have people "having fun" by spending 5 minutes between each pull talking when you yourself are there to get things done, not spend an extra hour there talking to people you'll never see again, wiping to everything, etc, it's easy for the game to stop becoming fun.

While rage isn't the best reaction to have, you do have to understand the reasoning for people not necessarily having fun because other people having their idea of fun can impact your fun if you don't share it. It's easy to have fun with the game but not with the people playing it at times.