Try to think of it from their point of view. If you already know what happens in the cutscenes and you've done the dungeon like 50 times, do you want to be forced to stand there for 40 minutes doing absolutely nothing because one player wants to watch the cutscenes? I agree that them mocking/shunning you was incorrect if they were doing so, but I don't feel you should be hating on them for going through the boss fights and finishing the dungeon either.