Strait Is The Gate*

That door looks like it opens inward.  Still, I'll bet anything it hasn't been opened in quite some time.

*Thank you, André Gide

Really?

That munchkin-sized door actually has a warning over it that says "Watch Your Head", complete with a figure hitting its head and "seeing stars"😆

René Magritte-ish Door

Redolent of "Ceci n'est pas une pipe".

An Urgent Message

Or perhaps a Zen-like one.