A few years ago, I came across an interesting theory of how to divide up stories implied in a talk by Lois McMaster Bujold: that stories are most usefully divided not by their structural elements, or their set dressing, but by the type of emotional experience they try to create. Romances, in this model, are fantasies of love; mysteries may be fantasies of justice or of understanding, and the latter category is shared with spy thrillers and Lovecraftian horror. Literary fiction about painful divorces may have more in common with The Texas Chainsaw Massacre than with Agatha Christie.
This goes back into what I've just been talking about — the ultimate emotional impact of a story being a chief determinant for how it's put together, and especially how it's ended.
What I think needs to be explored in detail, though, is not just the overall emotion but its implications. It's one thing to make an audience feel happy or sad or wistful or enraged; most of us can probably make that happen. It's another thing to do it according to a specific plan — to make it happen because you are trying to achieve a given effect that supports the rest of your story.
When Roger Ebert wrote about Akira Kurosawa's Ikiru, he called out the movie's peculiar structure. (Warning: spoilers.) About two-thirds of the way through, we jump ahead to after the death of the protagonist, and we learn about all the things he accomplished towards the very end of his life by way of the evidence provided by others. This is more than just saddening, as Ebert pointed out; it makes us emotional advocates for what we're being seen. We don't just feel what goes on; we the audience are aroused to make a case to the people in the story, and maybe also people outside the story, as to why our hero is in fact a hero.
To expand on LMB's formulation, the kind of emotional experience created by Ikiru is active rather than passive. It's not something we just sit back and feel vicariously; it's something we want to take back out of the story into the rest of our life. I don't think every story has to be this way, but I do think it's a goal to strive for.