Freud's psychoanalysis studies was one of the major key points in history of psychology. He explained three basic components of the human personality and those three parts exists together form our personalities plus our conscious mind and unconscious mind.
Often times experts describe this analysis as an iceberg. And here is why. Conscious portion of our characteristics interact with the world daily. On the other hand, our unconscious parts is not part of our known selves and stays well below the surface of awareness. These two together are components of our personalities. Discussed quite often, the id, ego, and superego, Freudians claim, compose the personality
Basic instincts like our sexual drive (libido) or aggressiveness is what freudians call the id. The id is like our most primitive impulses, which Freud thinks is the biggest factor of human behavior. According to Freud, pleasure principle is what drives the id and it seeks for constant gratification.
Second portion of the personality is the ego. Not to be confused with the term 'ego,' which is used moderately often in this society, Freud's definition of the term ego describes it as a principal decision maker in our system which we tend to show the world (conscious part). Unlike the id, ego is driven by the reality principle which does not emphasize gratification as much as the id but seeks for an appropriate outlet to solving conflicts.
Last comes is the superego; in easy terms it is just our morality. The thing that we all have and stops us from doing ungraceful deeds! The term superego literally means 'above ego.' I believe Freud's interpretation was that superego is something superior to the ego and it overrides the force ego holds and make us do what believe is to be good and moral deeds.