As in every other language, in Korean, what you say and do to greet people depends on the time of the day, the occasion and the person you’re greeting. Just saying “Anyoung” (Hi) is impolite. When you’re meeting someone for the first time, stretch out your right hand, and slightly bow. While this is being done, say “Anyoung haseyo!” which literally means “Are you at peace?” Shaking and bowing at the same time is a custom - be careful not to pump the hand of the person you’re meeting, just clasp hands briefly.