We’ve had some excellent discussions about API design over the years. Add to the list this piece by Joël Quenneville at Thoughtbot where he borrows a mental model from the world of MOBA games:

In gaming, MOBA (multiplayer online battle arena) players have a mental framework for describing just what kind of player is empowered by different characters. This framework describes all characters in terms of two statistics: their skill floor and their skill ceiling.