Why don't you knock off early
This informal usage of the word knock off here will automatically put a smile (but not too big so you can keep some dignity) on your face. This phrase means pack it up . . . go on, get outta here, scoot, have a good night! And, when this phrase is used, it's pretty clear that wherever you are is somewhere you're happy to be leaving early.
(The other prime definition of knock-off applies to the faux Rolex you bought on the street for $20—a not-so happy phrase if you thought you were sporting the real deal.)