This type of scenario has come up a couple of times and always makes me laugh. Upon disembarking the aircraft after a flight from Australia to USA or vice versa, a passenger comes up and says "so, are you flying back later today?"....or "do you turn around and go back now?"
This isn't necessarily a thick comment because there are actually some passengers who have no idea about our working hours and restrictions etc but my god, after operating a 12-15hr flight, can you imagine doing it all over again straight away