Pratchett takes on Grimm, Oz, and travel writing. Invents the Theory Of Narrative Causality. Yeah, it's fun, but it's also got some really dark and angry bits.

You can't go around building a better world for people. Only people can build a better world for people. Otherwise it's just a cage. Besides you don't build a better world by choppin' heads off and giving decent girls away to frogs.

This is why you need to learn to read the world before you start trying to write it.