Henry Kissinger restated the whole toilet thing this way:
"The only reason to sit in the back of the plane is because you either have diarrhea or want to meet people who do."
Southern Airlines (eventually became part of NW) used to have a great commercial in the 1970s involving the curtain...
It would start with a view of first class, and everyone would be laughing, drinking fine wine, eating cheese and having something of an airborne party. Then, the East German Female Olympic team member-esque f/a would open the curtain and walk into coach. People would be like chained up to the walls and it looked like a medieval torture chamber, she would then start barking orders at the poor slobs. It was funny.