fairchild....First of all, your English is lovely! I would've never guessed from your writing that you learned it in adulthood. Second, I know exactly what you mean by the slot between the door and wall; my experience is the other way around. I remember when I first went to Europe, to Amsterdam, and I came off the plane needing to go (I never do #2 on an airplane), and then the place I was staying at had this bathroom that grossed me out (not in terms of cleanliness), and I badly needed to go so I went to the local university and used the public restroom. I was amazed that each stall was practically a private room with a locking door, and no way at all anyone can peek through. It was such a marvel to behold.
BTW, anyone use those pit toilets they have in Asia? There's nothing to sit on!