This isn’t the why, but a result: “Guy Williams and his fellow visual-effects artists have spent so much time staring at Will Smith’s face, they’ve practically memorized his every pore. ‘We joke sometimes that we probably know his face better than his wife does,’ Williams told me in September, laughing. ‘I can tell you exactly how he forms a smile. I can even tell you the 12 different flavors of Will Smith’s smile and the subtleties of each one. It gets pretty obnoxious.'” Indeed. – The Atlantic