I just thought about how to make a story interesting and came up with a simple theory. The idea is to create rules and hints, so the reader already expects something to happen, but then let something else happen, which breaks these expectations. If the unexpected action is reasonable, the reader might find it more interesting, and the persons doing it seem smart. If it's unreasonable, it can be a joke. Even if the rule is pretty simple, it's not easy to follow this rule. It's important to establish the expectations before breaking them. And it's not possible to do it the same way multiple times, or even in the same way as other stories, else the reader already expects the previously unexpected. And it gets more difficult when the story gets longer or there exist more stories. Delays can also help to break expectations. When the reader doesn't expect it anymore to happen, at least not now, then it's a good time to let it happen. When some expectation is broken, it can still be a hope. Fulfilling unexpected hopes is probably the most satisfying way to break expectations, but this can only be achieved, when hopes are not fulfilled normally. Do you know of an existing theory about establishing and breaking expectations?