Lies help them be the center of attention and remain the center of attention.  Either their lies are painting themselves in a better light.  Or their lies are causing discord and dissension.  Or their lies are causing you to confront them- which of course means they are the focus of your attention.    I found it very difficult to talk to him or engage with him at all, once I came to understand that about 90% of what he said was a lie.  You just don't realize how much of conversation and relationship is based on the fact that you can believe that most of what people say is true.  But when most of what they say is false, it creates stress and utter chaos.  Around the time I filed for a divorce, I  learned that a lot of stuff I took to be true for many years was an utter lie.  I learned he went to school on an academic scholarship- he said it was a basketball scholarship- like that would be preferable!  I learned that he was not a youth basketball star who traveled the country with tutors, playing in all kinds of tournaments.  I learned that he hadn't been doing crisis counseling work at our church for two years- thus realizing that there were many period of time that he was unaccounted for!