It might sound a bit silly, but... There are words we often say unconsciously in our lives, haha. "Please help me just once." "Can you give me just one?" "I ask you just once." "Let me try just once." And so on. It's the phrase "just once"... hahahaha. Even though we end up doing it two or three times anyway, why do we shout "just once"?? hahahaha. I just used it several times too...