Sometimes we just know when a guy is playing us. He's feeling so sheepish it shows on his face, or else you've heard enough variations on his line to know it lacks any authenticity (such as when he says "I didn't even notice her"). On other occasions, though, it's not nearly as apparent. Perhaps he's had time to sturdy himself, to practice looking sincere or indignant. You may sense something's wrong but not know what. I'm happy to report that, according to body language experts, there are subtle indications that a man (or a woman, too, for that matter) is...