Freud believed that adult personality reflects how well your ego handles conflicts arising from the id and superego and which defense mechanisms you use to reduce your anxiety caused by conflict between the id's wishes and the superego's societal rules. Having taken a Childhood and Adolescent Development course at Pratt, I was familiar with Freud's theory of the id, ego, and superego. The id is responsible for instincts and pleasure-seeking, the superego attempts to obey the rules of parents and society, and the ego mediates between them. Freud states that your personality is determined by the relationship between these three systems. For example, if the id controls, then your personality is likely to be impulsive and driven by selfish desires. If the superego controls, then you are more likely to be rigid, moralistic and bossy.
There are widely differing opinions about Freud's legacy, ranging from a hero to someone whose patients would be suing him for malpractice if he were alive today. I personally think that Freud's theories cannot be taken literally and should instead be used as a guide when studying personality development. First, psychodynamic theories, like Freud's, are largely based on our unconscious, meaning they cannot be proven scientifically. Thus, most of Freud's ideas have been discredited due to their lack of falsifiability. Second, Freud did not confirm his ideas with larger samples of people and drawing universal principles from the experiences of a few patients is risky. Third, basing theories of development on retrospective accounts and fallible memories of patients is not always accurate. In addition, Freud's theories were developed in the Victorian age, a time of great social and sexual repression, which means that many of his ideas may not be applicable today. An example is how he believed anorexia to be caused by sexual repression, with the patient replacing sex with food, but most patients nowadays do not suffer sexual repression when suffering anorexia. However, Freud's contribution that the unconscious is an important role in personality development and psychology overall, is pivotal in our understanding of our actions, thoughts, and behavior. Overall, I think psychodynamic ideas are better thought of as metaphors and guides rather than literal truth, which is how I think most psychologists today view his work.