As we get older, we humans tend to think more about the past. After all, the future keeps getting shorter and planning for it takes little time and effort.
While it is always good to learn from the past, dwelling on it can be counterproductive and is often the source of needless regret. Some memories may seem vivid and accurate but the context in which past choices were made is often foggy at best.
Nevertheless, we continue to ponder the past, reliving joyful and painful events. Unable to shake the habit, it is best to give ourself a break. If we insist on accepting responsibility for our mistakes we must also take credit for our success; by acknowledging the complexity of life (including relationships) we learn to moderate this self criticism. We are, after all, only human.