I've always been fascinated with the very abstract, psychoanalytical concept of having a real self and an ideal self.
(While my more rigorous, cognitive side scoffs at me buying into such 'fluffy' concepts, another side that appeals to intuition tells me that the brilliant psychoanalyst Karen Horney had hit on an important subconscious concept (there - my use of the 'cognitive side' versus the 'intuitive side' to describe myself betrays this). Because how can something "else" tell "me" something; isn't that something "else" a part of "me" as well? And indeed, perhaps the use of the contemporarily established fluffy term "self" is shorthand for different mental modules or subroutines, each competing for a place in the consciousness, like a TV screen allowing only one channel to come to the fore.)
Anyway! I think a condition of human nature is that we create ideal selves that our real selves aspire to. But our wellbeing depends on the nature of that ideal, external, aspirational self. As Karen Horney suggests, in the instance of lying or being hypocritical, a false self is created. When a person creates a false self, the gap widens between who he is and who he can be or wants to be. Eventually, he can lose touch with his real self, which sets the stage for neurosis to develop, thereby affecting both his mental and physical health.