I'm a very, very good liar. I'm actually fairly sure I could defeat a polygraph.
I'm also extremely good at manipulation. I can grasp your weaknesses, hopes, fears, dreams, and bend you to my whims while you think I'm your best friend. I sometimes play up the Dumb Blonde stereotype, sometimes the innocent blond surfer-boy from California, sometimes the artistic loner, sometimes the misunderstood asocial. Sometimes the educated intellectual. I have many hats -- so very many hats. Which one is really me? You may never know.
But where I really and truly excel is knowing when people lie. My friends use my as a lie detector when they need to know the truth. The movies lie, not everyone has a tell. But there are definite signs. Voice tempo, cadence, frequency of eye contact.