I have a steadily growing theory that doors are the ultimate tool in assessing and explaining an RPG. Consider how the game has you:
* Open a door
* Pick a lock on a door
* Break down a door
* Find a secret door

Answers to these are super informative. Universal theory of doors?

Doors make for GREAT examples because the resolution is both easy to envision and easy to judge. It's got a core binary, which in turn makes it great for examples *even when they game rejects the binary*

That is, the door is such a clear example that it then becomes a meta example for why, in THIS game, we *don't* have you roll to unlock the door, we have you [SOMETHING ELSE*]

* Like the style in which you get past the door, or WHY getting past the door matters.

The idea of the "Secret door", similarly, is a door (ha ha) to a host of questions about how the game handles information, perception and secrets.

Hell, toss a door onto a map, and the rules around it tell you a ton about the game's action economy.

It's a CONSPIRACY OF DOORS!