There is a moment of realization when working with a person who seems nice on the surface that something is not right. It usually comes in a flash and without awareness, it retreats just as quickly. It is important to listen to those warning signals. Deceptive people often mask their deviousness, anger, manipulation, and controlling nature behind a kind façade. But even the best of deceptions are unable to be hidden all of the time. The problem is that most people ignore those signals through minimization (it wasn’t that bad), rationalization (there must be good reason), or justification (they must be having a bad day). The instinctive reaction is too often overlooked and this is how bad things happen to good people. But not all deceptions are the same. It is important to know the difference between an advanced con and a small ruse so both can be better avoided. There are levels of deception: Advanced – usually done by psychopaths and sociopaths. These deceptions are rather advanced

Source: The Levels of Deceptive People