Metta practice works it's magic by reflecting back our momentary experience so we can see where we are still holding. Embracing these parts of ourselves leads us to the boundless heart of metta.
This talk describes the use of contemplation and reflection in the meditation practice and explains the difference between reflective and discursive thought.
The mind is dominated by clinging to the past and the imagined future. Even the present is not experienced directly. Why do we so frequently avoid, now? What does it mean to live in real time?