Convention
One of the things I really don’t like is going against promises. Cutest things ever involve keeping some of the implied promises and conventions in mind.
One famous game, I’ve heard, promises a prizes. Turns out the cake is a lie. However, this wasn’t bad in itself: Instead of the cake, you get a joke, which is probably the next best thing. The condemnable example would have been to promise a cake and tell the player to go to hell in the end.
If you are given wonderful gifts, it is just a form of good manners to use the gifts responsibly. Throwing away wonderful gifts is sad. That is one of our conventions.