People with Borderline or Narcissistic Personality Disorders have a serious mental illness that primarily affects their intimate, personal, and family relationships. Often they appear to be normally functioning at work and in public interactions, and Narcissists may even be highly effective, in the short term, in some work or social situations. However, in intimate relationships, they can be emotional, aggressive, demeaning, illogical, paranoid, accusing, and controlling—in the extreme. Their ability to function normally or pleasantly can suddenly change in an instant, like flipping a switch. These negative behaviors don't happen once in a while, they happen almost continuously in their intimate relationships and most often, and especially with their Caretaker family member.