you haven't lived until you...
Usually followed by "done this" "eaten this" "watched some movie" etc. It emphasises that so many people have doen it that it has become part of life. Of course, this is most convincing coming from a short fat woman with greasy hair who looks like she's seen every movie ever, eaten every food possible, yo-yo dieted all the time etc.
You haven't live until you've watched the godfather trilogy.