'Do Not Open Until Your 1st Disagreement,' a note instructed
                                
                                
                                    (Newser) -
                                    The best wedding present Kathy and Brandon Gunn received at their Michigan wedding was one they never opened—at least not for nine years. That was because the gift from great-aunt Alison came with a special instruction: "On the plain white box was a card that read, 'Do...