“If past history were all there was to the game, the richest people would be librarians.” – Warren Buffet.

It was the beginning of the semester, and our professor explained the requirements for our class paper. He was on a bit of a tear, addressing one of his pet peeves:

“…And do NOT write me a paper that discusses how everything today would be different if the Germans had won WWII. You cannot know what would have happened because it did NOT happen. You cannot support such a paper with valid facts and proven academic resources. Do you know why you cannot support such a paper? Because there are no credible academic sources for you to use, that paper is a work of fiction. Please write that paper in your creative writing class.”

As you can see, this was a non-negotiable item for him. While he aimed to teach us how to write an academic quality paper about history, he also made an important point about life: You cannot go back and change your past. You cannot unsay things that were said or undo actions that were taken. Spending time on what could have happened or what would have happened is not very useful. Not in our personal lives and not in our professional lives.

You can look at the past and find ways to learn from past mistakes and successes. A paper with credible sources that showed how Germany and other countries learned from WWII; writing about the reasoning behind changes in political systems that could be verifiably traced to lessons from WWII, our professor would have loved that.

In your projects, you want to collect lessons learned and review lessons learned from past projects. The purpose is not to dwell on what happened and how it could have been different. You do not capture lessons learned to find someone to blame for your project mishaps. To improve your deliverability, the purpose is to apply those lessons learned to your current and future projects. If you look at a lesson from a previous project and learn that project had been executed differently, that is no guarantee that if your project followed suit, your project would have ended differently. Many variables contribute to project success. You and your team use lessons learned to respond to risks and evaluate future strategies.

The same can be said of your interactions with project stakeholders and colleagues. You want to learn from those interactions and grow. It makes no sense to replay a difficult conversation in your head repeatedly. Process what happened. Take note of some ideas for interacting in future and similar difficult conversations. Then let it go and move on. Use what you learned to have better stakeholder communications and build stronger professional relationships.