Did you know Korean has a bunch of ways to say goodbye?
These are the formal ways to say goodbye and what makes them different:
go" (가자, 가지마, etc)
Say it when: You stay, they GO.
계세요 is the polite way to stay "to be"
Say it when: You go, they STAY.
바이바이 (ba-i-ba-i) Bye-Bye!
잘가! (jal-ga) Go well :D
내일봐! (nae-il bwa) See you tomorrow!