Eons ago I had a boyfriend who bought a home. The house had lots of nice kitchen cabinets. They also lined all of the walls in each bedroom with upper kitchen cabinets. Good for storage but very, very odd.
When DH and I were looking at houses, we saw one that had a beautiful stone fireplace in the corner of the living room. It really was beautiful. The other downstairs rooms were large but needed some work (okay with us). Upstairs, we opened one of the doors to go in, and were looking at the bare pipe for the fireplace. Yep, they had just cut a hole in the wood floor and ran it up. We had to turn to the side to squeeze into the room (it was a larger bedroom and this was the only access). That had to be a fire code violation.
I'd love to have secret rooms and passageways too. Very cool.