"Look not mournfully into the past. It comes not back again. Wisely improve the present. It is thine. Go forth to meet the shadowy future, without fear." - Henry Wadsworth Longfellow
We must acknowledge the past because it has played an important role in shaping who we have become today. Anything that we have any degree of certainty about has occurred in the past. We know what happened, who was there, how events transpired, and how problems and issues were eventually resolved. We exist in the present, but we are never quite sure of how the present will change from moment to moment, and the future is always highly uncertain. Therefore, it often becomes tempting to live in the past because, unlike the present and future, it is not unknown. However, there are several reasons why this is not always a productive way in which live.
First and foremost, the way in which we live in the past is of vital importance. For example, the inability to let go of the guilt, shame, and pain that may have dominated the past is not emotionally healthy, and does not contribute anything positive to the present. However, when we learn from the mistakes of the past, and bring those lessons with us into the present, then even a negative past can serve us in a positive manner. As Lyndon B. Johnson once said, "We can draw lessons from the past, but we cannot live in it.".
Interestingly, it is also rather unhealthy to spend too much time dwelling on the past in a nostalgic manner. We may not be feeling any negative feelings about ourselves when we yearn for the past in this way, but it still prevents us from living fully in the present moment. It is far better to strike a balance between being mentally present for life as it continues to unfold while, at the same time, allowing ourselves to occasionally think back fondly on the favorable memories of the past.
The fact of the matter is that the past is gone. Good, or bad; it is incapable of returning, and cannot be changed in any way, shape, or form. Living in the past allows for the possibility that we will miss the abundant gifts and precious moments of the present. We do ourselves a far greater service when we accept the past as a series of positive and negative learning experiences which, when viewed with the proper attitude, will always result in our continual growth. L. Thomas Holdcroft said it best: "The past is a guidepost, not a hitching post.".