They see themselves as love-able i.e. worthy and able to be loved. When through various forms of abuse and neglect a child fails to get this mirror of love, two things happen. First the child begins to take in the feeling of defectiveness or un-loveability. If mommy or daddy treats me this way, it must be my fault. A second thing also happens.
Children are masters at devising strategies to get love or prevent abandonment.
If I'm perfect, then mommy or daddy will love me. But the result will always be disappointing. Nothing can replace self love. But like anything worthwhile, it takes effort. The key is in the way we experience our memories of parenting.