Your best teacher is your last mistake.
Whenever we make mistakes, we have a choice. Some people choose to blame, avoid responsibility, gaslight etc. What you should be looking at is understanding what went wrong, LEARNING from it, which in turn TEACHES you to – as best as you can – avoid making the same mistakes again. Your last mistake is your best teacher as there’s often a negative emotion associated to mistakes, which in turn can help absorb the lesson better.