What's wrong with eating alone?
When I was in the States, it was entirely fine for people to be
eating alone. You see them everywhere cafeterias burger joints
etc.
I use my lunch hours to eat alone and read the papers at the
same time. It appears there's a stigma attached to being alone
isn't it?
There's also the habit of buying take outs. You avoid the evil
eye from other customers in search of seats during the peak hour
lunch/dinner time and then there's the habit of squaring anything
edible because you're having it by yourself anyway. 
