“One never notices what has been done; one can only see what remains to be done.”
This is only a part of the meaning expressed by Marie Curie above. As you may already know, Marie Curie was a physicist and chemist from Poland who later took on French citizenship. She worked alongside her husband and was subsequently honored with two Nobel Prizes, largely for her work in the field of radioactivity.
In fact, she pioneered the field, as she is generally credited for discovering a theory of radioactivity in the first place. She also discovered two new elements: polonium and radium. She was always pushing forward and looking ahead to what had to be done next.
She certainly encountered her fair share of problems and failures, but she did a great job of overcoming them. We all make mistakes. You should acknowledge them, to be sure, but the key is to see how you can rectify these mistakes and move forward. What else needs to be done? What other goals do you have?
Find the balance. Recognize and be grateful for the work that has already been accomplished, but also look ahead for more progress, renewed innovation, and the next major discovery.