Came here via metafandom, and yeah, I came to the conclusion a while ago that either your brain processes fiction as if it were real or it doesn't, and if it doesn't you'll never understand fanfiction. To me, "What happened before?" "What will happen later?" "What are they thinking?" are questions that pop out automatically whenever I'm properly involved in a story. It doesn't mean I don't know it's fiction, just that the joy of fiction to me depends on imagining an entire world outside of it. So yes, I quite agree with you.