Kurt Vonnegut: I want to share with you something I’ve learned. 
Why chart the emotions of the protagonist to evaluate the story? The value of a story is not in how happy or sad the protagonist was - but how it makes you feel.If I had to evaluate stories, my vertical axis would have 4 parts.  From top to bottom:* Unpredictable and irrational* Surprisingly Unpredictable* Tolerantly Predictable* Predictable and staleThe closer the story is to "Surprisingly unpredictable" the better it is.Cinderella, Kafka, Hamlet - all reach that point.(But to be fair - Cinderella reaches that point only because its amongst the first few stories you ever hear.)Titanic reached that stage for many teenage girls by killing the hero.The best book I've read - Foundation Trilogy by Isaac Asimov reaches that "surprisingly unpredictable" point too.