Children's books aren't textbooks. Their primary purpose isn't supposed to be "Pick this up and it will teach you this." It's not how literature should be. You probably do learn something from every book you pick up, but it might be simply how to laugh.
J. K. RowlingWhere is Wood?" said Harry, suddenly realizing he wasn't there. "Still in the showers," said Fred. "We think he's trying to drown himself.
J. K. Rowling