The core problem of the borderline personality is instability. You tend to feel your emotions very strongly, and find it hard to regulate them. You can be impulsive and sometimes self-destructive. You have little trust in yourself but also feel you cannot really trust others. You tend to feel easily rejected and are constantly afraid that the people you care about will abandon you. This can result in you not starting intimate relationships at all or, on the opposite, in you clinging desperately to the relationships that you do have.