문제 없어 / "Bai-bai"

The phrase 문제 없어 (munje eobs-eo) means "no problem"; useful when responding to any number of inquiries, but perhaps most importantly it signals that you are having a good time while getting hammered on 폭탄주 (pogtan-ju) or "bomb drinks".  If your host asks "it's okay?", knowing this little snippet of Korean will make them laugh, display that you are sober enough to continue drinking, and having fun.

If at some point a co-worker mangles this phrase, and then begins speaking in Spanish, your Korean host may simply waive to them like a child and say "Bai-bai" to indicate that Elvis has left the building.  P.J. O'Rourke said it best: the Irish of Asia.  I'm a big man and I held my own last night, but it's daunting to see a man half my size keeping pace with the soju bombs; in the States it would be expected that someone my size could pound a few shots strategically hidden in a similar number of beers, but here they seemed genuinely surprised.  If they tell you it isn't a competition, it's because they are assuming it probably isn't much of one, and they're likely correct; these guys do this once or twice a week all year long.