The memory of difficult past experiences, which leave us with a legacy of pain, regret, sadness etc, can dominate our present and hold us back. We may need time for healing and to process the feelings (if necessary with professional support) but for the sake of our happiness we need to put the past behind us and get on with our lives. But more than that we can regard the past as a resource we can draw on for our growth.
If we dispassionately reflect on past events we will learn a lot about ourselves, who we are and what we want from life, as well as gaining insights into what we might do differently if and when presented with similar circumstances in the future. Learning lessons does not necessarily mean avoiding similar situations in the future out of fear that the same outcome will result, rather behaving differently to get a better outcome.
It can be true that ‘what does not kill us will make us stronger’ but this requires mental discipline to draw a line under the past, and avoid replaying the old mental tapes related to these events. It is far better to focus on and appreciate the gifts and resources we have now than to become a victim of our pasts.
Happy memories can lift our spirits in challenging times, but arguably difficult experiences represent a greater resource. Similarly we learn more from our failures than our successes. Transformational moments in our lives are more likely to be associated with how we deal with challenges,failures/mistakes than the good times/successes. This is not to say that we should wish for more grief in our lives !