I think that with memories, no matter whether they were pleasant or not, make us who we are today.
We may sometimes look back onto them and regret that we didn't do what now seems to be so obvious to us, but it's the little mistakes and hurt that we've experienced that make us realise and develop the importance of our individual values, constructing our view on the world.
I know, everyone is always going to have a memory that they'd never want to revisit, and keep locked up into the depths of our abyss of a mind, but even then, even without re-opening old wounds that never fully recovered, we can still try to pick ourselves up, and, even if entirely broken inside, continue walking forwards until the very end.