After establishing metta with an "easy being" we can train the heart to offer goodwill to a person we do not know, and also to one who is challenging for us. Our hearts grow stronger as metta deepens and expands.
Forgiveness practice complements and strengthens brahma-vihara practice. It can also clear subtle obstacles, allowing concentration and insight practice to deepen.
Liberative, or Transcendent, Dependent Arising describes an arc that runs from suffering (dukkha) to liberation, including many beautiful qualities like faith, joy, and tranquility. It shows how the mind gradually untangles through a lawful process.