One common test of abstraction is to explain what this means: "people in glass houses shouldn't throw stones."
I've heard answers ranging from "it's like shooting yourself in the foot" ... to "you'll break the walls" ... to "people are watching me!"
I just hope a paranoid patient never walks into this structure.
Sheesh, I have a hard enough time going when there's someone in the adjacent room.
somewhat appropriately, this tip comes from The Proximal Tubule