In Jungian personality theory, people fall into a number of types. Firstly, individuals fall somewhere along the introversion-extroversion continuum, depending on whether they are primarily oriented to their own inner reality, or the outer world. In addition, everyone has a dominant function, one of: thinking; feeling; sensation or intuition.
But from a depth psychotherapy perspective, what is particularly important about Jungian personality theory is the orientation where the individual is weak. FOr it is those weak parts of the personality, that the person is seeking to develop and to come to wholeness or individualtion. So, we can learn a great deal about ourselves, if we can undersatnd our areas of inherent weakness, and where psyche is trying to work towards wholeness.