I heard that there some say that single men should not sit at the corner of the table, because it could lead to someone staying single forever. Is there a source for this idea?
Poking around on the Internet I couldn't find any references to this particular adage. But the concept is simple enough, I think, that its source can be inferred. Historically, parents (mothers in particular) want their children to find love and to marry well. Just like at little league sports events, they watch from the stands and develop a neurotic interest in the success of their children in this pursuit. And they notice minor things, like the fact that boys and men positioned in the middle of a long rectangular table have greater access to the attention of the girls and women at the table.