Ideally, an interface will surface the deepest principles underlying a subject, revealing a new world to the user. When you learn such an interface, you internalize those principles, giving you more powerful ways of reasoning about that world. Those principles are the diffs in your understanding. They're all you really want to see, everything else is at best support, at worst unimportant dross. The purpose of the best interfaces isn't to be user-friendly in some shallow sense.