Everyone lies to an extent. Most of us lie regularly and don’t even realize it, whether it’s to protect yourself from getting hurt or out of concern for another’s feelings. This kind of lying is accepted as a social norm by society, for better or worse. But for those who take lying to an unacceptable level, dwelling into pathological or habitual lying territory, there were psychological reasons for their casual approach to the truth.

 
The reason your cheating spouse, a thieving relative or business acquaintance is lying to you is much more deeply rooted than their desire to benefit themselves. At some point in their life, most likely when they were young, they got something they wanted or advanced with lying. All four year olds lie, but the differences with lifelong, career liars are no one ever corrected them or told them not to lie. This is often a culmination from trauma, neglect or simple lacking adequate attention.

 
Eventually, as the habitual liar grew up and continued telling more and more lies, they actually became more comfortable lying than telling the truth. And in a world wherein honesty is always the best policy- where a liar is not a valued member- a pathological liar has a poor self-image and subsequent low self-esteem. This low self-esteem is something they try to overcompensate for with more lying, pinning themselves in a vicious circle and an increasingly entangling web of lies.

 
Ultimately a liar is trying to convince themselves a lie is fact just as- if not more- than the person they are lying to. So outrageous tales, backpedaling when confronted with lies and just all around deception is just a casualty in a liar’s quest to advance themselves are far as possible through dishonesty. And what’s more, the casual liar won’t even lie to gain popularity or compensate for short comings once lying has become a habit; it will just be for the thrill.

 
So if you are associating with someone on your own accord who you have discovered to be a pathological or habitual liar, you are better to cut ties with them anyhow. This is because constant lying is typically an indication of deeper issues, such as narcissistic personality disorder, antisocial personality, or any number of other mental issues.