The worst part is when the customer _thinks_ they know the rules, and then don't (consciously), and you have to help them through that cognitive dissonance of r

The worst part is when the customer _thinks_ they know the rules, and then don't (consciously), and you have to help them through that cognitive dissonance of realizing that the business rules they "know" aren't actually the same as the ones they know. A coworker of mine used to term this, "Applied Philosophy." There was a post on HN a few years ago, where a game developer had a game where all of the users were asking for an Undo key. This would have completely broken the game! So he looked into his data, and figured out that what people were mad about was moving into a stream tile and taking damage or dying. So instead, he made it impossible to move onto a stream tile, and the problem was solved.