I'm strange in that in fanfic, I want a happy ending. I will read the end of a story if it's not an author I know and trust. In a mainstream book, I don't need to know the end. Even if one of the main characters is killed off, I have no vested interest in them so while it might be sad, it's not emotionally hurtful. I love my boys so I want them alive and well (and happy) at the end of a story.