I was thinking that it might actually have some sort of historic reason behind it, though. Like, during the American Revolution, the term "Yankee" became a popular name for people in the colonies. Of course after the revolution, a lot of history happended in the US to where Yankee only refers to people in the North East. Today though, I could visit Britain and still run the risk of being called a Yank simply because I'm american (though I'm from the South, so that would... not be good).