There are some people that have shy bladder syndrome wherein they do not like to pee when other people can see them. I would assume that there are similarly shy poopers. These are serious psychological conditions folks...nothing funny about a person who really needs to use the restroom but is overcome by anxiety because there are other people around. (Actually what am I saying, that's hilarious.) Here are two bathrooms I found on the internet that must be the epitome of evil for people who suffer from either or these conditions.
This second set of pictures is an artist's installation that was in Basel, Switzerland for a while. The bathroom is surrounded by a two way mirror, if you didn't get that from the pictures :P