you can do a whole lesson on farewell celebrations/ceremonies. different cultures have different ways of saying goodbye. in some, it's ok to be happy, in some it's not. are you blessed by a religious person as you leave? do your friends throw you a drunken party at a bar? maybe your family makes you a nice dinner at home. maybe people give you gifts, or lucky charms. there's also the song "farewell, goodbye, Auf Wiedersehen, goodnight."
So Long, Farewell lyrics - Sound Of Music lyrics it's cute.