Lying 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.

If a person feels terrible, it usually should not be shown or acknowledged during a greeting exchange. Instead, the unhappy person is expected to conceal negative feelings, putting on a polite smile to accompany the “Just fine, thank you, and how are you?” reply to the “How are you today?” The true feelings will probably go undetected, not because the smile is such a good mask but because in polite exchanges people rarely care how the other person actually feels.

MOST LIES succeed because no one goes through the work to figure out how to catch them.

Emotions Revealed: Recognizing Faces And Feelings To Improve Communication And Emotional Life.

People also smile when they are miserable.

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.

Crucial to how we feel is being aware of how we are feeling in the moment. The sine qua non of that is to realize that you are being emotional in the first place. The earlier you recognize an emotion, the more choice you will have in dealing with it. In Buddhist terms, it's recognizing the spark before the flame. In Western terms, it's trying to increase the gap between impulse and saying or doing something you might regret later.