The Korean language is filled with honorifics, meaning there are different ways of addressing people according to rank and seniority. Additionally, like the other main Asian languages, there's a word for "foreigner" that you hear over and over again. In Korean, it's 외국인 ("oegugin", sounds like "way-goo-geen" with hard g's). It's impossible to go anywhere in Korea and not hear this word. Just like the word "foreigner" in English, it can be used in different ways. It's often a non-malicious way of talking about Westerners, since it's slightly shorter than 외국사람. But it can also have the negative connotation of calling someone a foreigner, an outsider.
On an unrelated note, Koreans often address each other by title, like "Teacher", and they add 님 ("nim") to the end as an honorific (e.g., 선생님, or Teacher).
Which brings me back to my story. I went to a coffee shop the other day, and as I'm paying, I could have sworn I heard one of the girls behind the counter say to the other one "외국인님 있어요", which is a strange combination of "foreigner" and the honorific. Like I said, I don't speak Korean, but it would probably be equivalent to calling someone "Mr. Foreigner" in America. I laughed, and then she looked away embarrassed, because foreigners aren't supposed to understand Korean. Heh.