Imagine the scene. You are going about your daily business when there's a buzz on your phone. “Ah, It's my sweetheart,” you notice, with a frisson of romantic excitement. “I wonder what she wants.” You reach for the phone, the possibilities whizzing through your mind. Could it be a seductive photo, along with the offer of a hot weekend away somewhere? Or maybe she wants to compliment you on that awesome sandwich you made her for lunch? Do we need milk?