I spent a lot of my early teens asking this very question. I wanted turn back time because I lost a friend, and blamed myself for it. I was very passive about her depression, writing her feelings off as something she would “get over, eventually”. Only when she took her live I realized how wrong I was, and that I should have done something besides waiting for her to “get over it”.
However, I’ve matured a lot since then. And now if I had the ability to turn back time to get her back, I wouldn’t do so. Of my core philosophies in life is that we are, in many ways, formed and changed by our experiences. Even if some of those experiences have been awful for me, I’d like to think they’ve made me stronger as a person. Mistakes are what allow us to learn. I think that people don’t really realize that. People fixate on their mistakes, rather than realizing how much they learned because they made a mistake.
Because of her death, I’ve learned to be far more proactive in life. I’m not going to waste my time worrying about “what I could have done” and instead worry about “what I should be doing.” By focusing on the present, I’ve been able to help people. So in that sense, I’d like to think I’ve grown from my mistake.
There’s one more thing I do to. I don’t call mistakes “mistakes” anymore. Instead I refer to them as “experiences”. I think the word experience allows people to realize they can learn from what they’ve done, rather than blame themselves endlessly. Because blaming yourself doesn’t really accomplish anything. It’s useless to beat yourself up. That’s why I prefer to learn from an “experience” rather than blame myself for a “mistake”.
Moral of the story is, not even Jupiter can find a lost opportunity.