Aristotle was one smart guy. I had to remind myself today of his storytelling formula:
1. Pity: make your characters experience some undeserved pain (it has to be undeserved, or it won't work). The audience will feel pity, and you got them.
2. Fear: now let loose the monsters. The audience will be afraid for your characters because they care. Make the monsters do worse and worse things to them.
3. Catharsis: at the end of your story free your characters of all misfortune. The audience will sigh in relief and experience catharsis.
Think of your favorite stories. They all have this formula, don't they?