You can see it in the media every day; people who say something that is not the truth.
And some of them are so well prepared we don't see the signals.
Sure, there are also those who lie and everyone recognizes it immediately.

Many of my interviews on TV start with the question if Mr. or Mr. X said the truth or not.
And because I am not a psychic mind reader but a body language expert I give an educated opinion based on the verbal and nonverbal expressions I can see.

As a result of my presence in the media I am often asked if I am willing to train people to fake their body language.
But, because of the lack of congruency it is not a good idea to fake body language.
The chance is high that gestures, micro expressions and verbal content are not congruent.
The result is that the receivers tend not to believe what they hear.
Even the best trained body language experts will show contradictory signals.
Some of those micro expressions will flash across a person’s face in a fraction of a second.
These signals are missed by the untrained observer, but they are sometimes unconsciously registered.
And many signals can be faked only for a short period of time.
While some signals can be learned, others cannot be consciously faked.
Professional observers learn how to separate the real gestures from fake ones, so that a genuine person can be distinguished from a liar.