Sigmund Freud presented the first comprehensive theory of personality. He was also the first to recognize that much of our mental life takes place outside of our conscious awareness. Freud also proposed three components to our personality: the id, ego, and superego. The job of the ego is to balance the sexual and aggressive drives of the id with the moral ideal of the superego. Freud also said that personality develops through a series of psychosexual stages. In each stage, pleasure focuses on a specific erogenous zone. Failure to resolve a stage can lead one to become fixated in that stage, leading to unhealthy personality traits. Successful resolution of the stages leads to a healthy adult.