One Cultural Component in Korea

Dont call someone older than you by their first name.

People don't speak in the first person in Korea. They dont often use the pronoun 'you' either, especially to someone older than you. While you can use the name of a younger brother/sister or a friend of the same age, you cant use your colleague's name, boss's name, or the name someone you dont know well. In the family or at school, girls can call an older brother, older male friend '오빠' (oppa) and boy can use '형' (hyung). Likewise, girls can call an older sister, or older female friend '언니' (eonni) and boy can use '누나' (nuna). in the office, it's a good idea to add '님' (-nim) to the last name and job title of all older people. Among colleagues,they add '씨' (-ssi) after a man and woman's full name.