You would call someone "garbongo" when they are clearly wrong.
Garbongo means that something or someone are lower then trash and deserves to be burned like the filthy garbage they are
GARFUNGLE is a very majestic and great being. He is so very majestic and wants Vincent to lick his big sweaty toe. There is only one GARFUNGLE in the universe. So if you ever find one then it is probably not a GARFUNGLE cuz there will never be another GARFUNGLE. Btw GARFUNGLE is very majestic if I haven’t mentioned it already.