This person has an ethical problem. Sometimes Liars fall into unethical behavior because it's the easiest way to get what they want; they seem to get away with it, so they think, "Why not?" Perhaps the Liar was brought up in the business world by unscrupulous people and doesn't know any other way to operate. Or perhaps the Liar believes that outfoxing someone else makes him smart. Some people believe that the ability to get something out of someone else by questionable means is the very essence of power.