At the end of The Wizard of Oz movie, Dorothy wakes up in her bedroom to find that the world of Oz was just a dream. Her subconscious substituted the characters and events from the real world to create a much more colorful fantasy world, but that's all it is--a fantasy.
I hate this ending. It's a total let-down. So I was quite happy to find out that the book the movie was based on, The Wonderful Wizard of Oz by L. Frank Baum (my review at PGP), doesn't have it. Dorothy does travel back to Kansas, but the land of Oz is just as "real" as Kansas (especially to Dorothy). And that isn't the only adaptation I've come across that does this: in The Nutcracker ballet, Clara wakes up on Christmas morning to find her journey to a castle with an enchanted prince was nothing but a dream. Depressing! Does this happen in the story Nutcracker and Mouse King by ETA Hoffman? Nope! Instead, Clara winds up traveling back to the prince's castle at the end (review here).
Obviously these are only two examples, but I have to wonder why the film and stage adaptions of these fantasy novels went that route. "Ooops, it was just a dream," is a TERRIBLE ENDING. Terrible! Personally I think it would make more sense for the world to remain a reality in the context of the story; but by saying it was just a dream, the adaptations kind of render what just happened irrelevant. It's not as if they didn't have an already-good ending at their disposal, yet they went out of their way to set the story firmly back in "reality."
One of my theories for this is that movies and plays are more "real" than books, in a physical sense. Everything that happens in a book happens in the reader's mind--which is one of the reasons two people can have such different experiences reading the same book. But movies and plays happen in real time and are experiences usually shared with a group of people in a theater. The objects on stage and in the movie take up actual space, and the characters are brought to life by real people. Maybe as a result, people who tell stories through plays and movies are more concerned with reality and making their movies "realistic." That still doesn't quite fit, though, because there are plenty of fantasy films that never reference reality of any sort.
Maybe it's because both Clara and Dorothy begin their stories in the "real" world, travel through a fantasy world, and then return to their normal lives, thus creating a permeable reality. Tchaikovsky and The Wizard Of Oz's studio didn't want to encourage escapist fantasies, which--fair enough. That's some dangerous stuff right there.
Can you think of any other book adaptations that turn a fantasy or adventure into a dream that didn't "really" happen? Why would anyone do that? Why?!