Be it playful design or gamification: It usually takes about five minutes until the Mary Poppins tune “Spoonful of Sugar” is evoked. This talk will explain why this reference is both true and false, how the movie entails two radically divergent theories of fun that match what we know in psychology and educational research, and how to translate this into designing for fun. My talk given at Gaminomics 2015, June 11, 2015 in London.