Smiles are probably the most underrated facial expressions, much more complicated than most people realize. There are dozens of smiles, each differing in appearance and in the message expressed.
Paul EkmanLying is a deliberate choice to mislead a target without giving any notification of the intent to do so. There are two major forms of lying: concealment, leaving out true information; and falsification, or presenting false information as if it were true.
Paul Ekman