I agree with what the mod and the others have said, but I also think that part of the nation's personalities are just that; their very own personalities. After all, while they're not completely human, they do have a bit of their own personality.

Take for example North Italy: Because of his experience with HRE, he doesn't like to be left alone. It has nothing to do with Italian people being clingy, it's just one of North Italy's little quirks. Did that make sense?

Well, that's my two cents.