My house is built on top of bentonite clay (I think that's the term). My doors would stick if there weren't gaps. I have a system where I measure the level across the house and adjust my teleposts every year too.
Doors. That one is a double whammy, because even if I force myself to unsee that a wing was installed unevenly, eventually gravity itself will remind me, as it will start closing on its own, or stopping at a different angle than other doors in the house, etc.
