I know several people who have told me as adults that when they discovered they could end a creative writing assignment by waking up from a dream they genuinely believed they had come up with the Best Thing Ever. English teachers and the judges of short story competitions would say otherwise.
Maria Nikolajeva writes about the dream ending and similar tidy conclusions in her book Children’s Literature Comes Of Age:
Children’s books with ready solutions bind the child’s imagination and free thought. It is treachery towards the modern sophisticated child reader to offer a “rational” explanation at the end. “And then he woke up and it has only been a dream.” We should not think that this ending is a thing of the past, for we remember it from Alice In Wonderland. It is repeated in much later texts, and one discovers it somewhat reluctantly in Mordecai Richler’s prize-winning book Jacob Two-Two Meets The Hooded Fang (1975) and in a many even more recent texts. Critical and creative authors find such resolutions very unsatisfactory, and regard the open ending as the only possible way of appealing to modern young readers.