Gaps in the toilet doors
Shared experiences are the hallmark of your years in the education system. Taking the same classes, eating the same food, watching the same person slip over in the cafeteria, and spill the contents of their lunch trays everywhere.
There is such a thing as going too far, however, and really they need to do something about the fact that in a lot of American schools, you can see through the gap in the cubicle wall directly across to the person sitting in the next stall. That is too much sharing.