It was hard to tell what was making Andrea Mitchell angrier: Bill O'Reilly's assertions that NBC has a liberal bias, or his repeated and perhaps ungentlemanly references to the lady's "30 years" of experience. In any case, the look on Andrea's face was unmistakable: she was not the happiest of campers. Mitchell appeared on this evening's Factor for purposes of touting her new book. But kudos to O'Reilly for taking the occasion to directly confront a leading NBC light with the network's undeniable leftward tilt - which Mitchell proceeded to flatly deny. This is must-see video, which you can...