Question is, how much of their time can you waste, and how much time are you willing to invest in the process for entertainment value?

Learning something.

If I come across a bookcase embedded in a wall - 99% chance it's a 'hidden' door. Bookcase sitting against a wall, not so much.

Why do none of these 'hidden' door bookcase solutions end up looking like a bookcase sitting against the wall?

Well, Hello there!