It's never a once off process, sometimes letting go threatens to break you as you realize you have been holding on for so long, there's nothing but the bitterness, hatred and consuming anger. All depression is created by subdued anger for various reasons and various personality traits, but guilt regarding the anger is greater than the anger itself and so suppression of anger leads to confused signals in our brain and the symptoms of depression kick in and assume control.
Mark Virkler said the pure in heart have Faith, Hope, and Love in their heart. The pure in heart see God. If there is something beside these like fear, bitterness, anger, hatred-a negative emotion that is not being pure in heart.