In my opinion, knowledge of the past is a critical resource to have; and one that affects our actions and decisions in the present and the future. When you have knowledge and understanding about past failures and mistakes, you are able to better avoid repeating them in the present or the future. Likewise, knowing and understanding the positive decisions and actions of the past enables to have a solid foundation upon which to base our decisions and actions on. Also, knowing the consequences and results of past decisions and actions give us reasons to avoid making the poor decisions of the past.
Thus, knowledge of the past is an extremely valuable asset to have; and we should continually seek to understand the past in order to prevent ourselves from making poor decisions in the present and the future.