Of the many ways that exist to classify and conceptualize individual differences, some are obvious and somewhat visible, such as gender, race, language, origin and / or social background. Other forms, perhaps not as visible, are nonetheless influential distinctions such as culture or personality. The personality, like many things in life can be difficult to explain, is what makes every human being different, unique and exceptional. Today, the personality is an issue around the world. It reflects who we really are. Although most people use the term "personality" to identify the most obvious characteristics of a persons, psychologists are addressed in regards to this to explain why people with similarity in genetic background, experience and motivations can react quite differently to the same situation, and to explain why people with different genetic, experience and / or motivations past, but similar reactions to a single event. I intend to share with you my account of the personality, as it defines me as an individual and finally I will discuss what factors make a personality test is reliable and valid.…