This quote comes from Game of Thrones, where Ygritte says it to Jon Snow. It became one of the show's most quoted lines because it sums up Jon's innocence and stubbornness in a memorable way. After airing, the phrase spread widely in memes, reaction videos and fan edits as a shorthand for calling someone uninformed or naive. It still gets used years later because even people who have not watched the series often recognize the line and its playful, mocking tone.