Mindfulness practice helps us slow down and access deeper levels of experience. By touching positive emotions while meditating, we can learn how to nurture them, and by touching negative emotions, we can learn how to transform them.
In Thich Nhat Hanh words:
When we are able to touch our habit energies and transform the roots of violence, despair, fear and anger in our store consciousness, transformation at the base occurs.
Thus mindfulness practice assists the process of healing painful emotions, and discover their hidden wisdom.