Years ago, I was privileged to study with a Zen master, who shared with us important lessons about "letting go." He explained that we tend to cling to what he termed, "the imprisoning chains and suffocating ashes of the past." Before we can learn how to transcend the ego, we must first learn to let go of the attachments (whether pleasant or unpleasant) it has formed to events from that past.
Much later, I encountered the Sedona Method. Yet another mentor helped me understand the concept in terms of three simple questions, best prefaced with their answers: "yes, yes, and now." (1) Would you let it go if you could (i.e., if you were actually able to do so)? (2) Can you live without it (in the sense that you certainly cannot live without air, water, food, etc.)? (3) Since you would let it go if you could, and it is quite apparent that you can live successfully without it, when do you plan to do so? As simple as these questions appear, their therapeutic value is profound, and many clients have learned how easily they can indeed "let it go."
All too often, our psycho-emotional growth is impeded by of our refusal to acknowledge things as they are. All too often, the anger, bitterness, frustration, resentment, and related negativity to which we cling will also affect our bodies adversely. And (eliding into more esoteric realms) all too often our chakras become blocked, and the toxins we won't "let go" may even dampen us on the spiritual level.
Of course, Zen is not psychotherapy, and the Sedona Method is not a panacea. Both, however, have influenced my work, and their unifying thread is freedom from the past. The emotions connected to one event or another, the related ego-attachments associated with those events, and the time and energy we squander while mired the past will invariably prevent us from living fully in the present.