You Can't Go Back In Time and Fix That ONE Mistake
Many is the story of going back in time to fix a mistake.
Unfortunately, time doesn't work that way. (No, it doesn't work that way either, all you who thought, "the past is fixed".)
Almost all stories of time travel are completely fiction, especially the ones in "science" text books.
The reality of time, and time travel is actually quite boring. BUT! It can be used for great healing. And this is why i will write about it.
Going back to stop Hitler
So many people, if you ask them about what they would do if time travel was real, would say, i would go back and stop Hitler.
The thing is, Hitler is a focus of many, many, many stories. The stories culminated in Hitler. You could say, that Hitler was the focus of the time lines. Bringing many of them together.
So, if you went and shot Hitler, and came back forward in time, there would still be Hitler. Maybe a different person, but Hitler would still exist.
No matter how many times you killed, stabbed, blew up, Hitler, Hitler's mother/father, it would always be the same, Hitler would still exist.
You would have to HEAL every person who was tied in with the story of Hitler. And that was most of the world. After healing that, there would probably not be a WWII or a Hitler. Germany would not have been persecuted for WWI, and everyone would be a lot better at negotiating for what they needed. However, that is a LOT OF HEALING.
All in all, you cannot go back in time and stop Hitler. Hitler is kept in place by many, many people's thoughts, he is not just a person that can be shot.
Your past doesn't exist, except to you.
Here is a weird one. Most people believe that their past is something indelible. That it can't be changed. It is the past.
However, there are spiritual practices, such as "reparenting" where you go into your mind and change your past. Like, give your inner child a good mother, instead of the abusive one you had. And if you do this enough (this is a weird measurement. It has to do with you rewriting your story, and how much you will believe in and give up the trauma from it) then the past you are imagining become the past everyone else remembers.
Yes, your friends / family members will remember the new story that you created.
The big trouble here is they may have never remembered the abuse you built your whole life around.
What you remember is most likely not what others remember about something that happened. Everyone remembers more of what they find important, and less of what they don't even notice. This varies from person to person, and so you expect the memories to be different. However, even accounting for this, people remember things happening differently. Often very differently. Like, it was someone else who jumped on the table and danced naked.
Your past is as changeable as your future
This is also to say your past is as fixed as your future.
A good portion of why people do not believe in free will is "destiny", but that is usually almost all You pulling in a future that you want.
If you have planned your life to end up in San Diego, you will find yourself moving west in the present. And that moving west will seem like it is something outside of you, guiding you. Like you do not have a choice in where you go.
The "ending up in San Diego" was/is your free will.
Your future pulls you towards it. And that is connected to the backdrop of your life, your past. These two things that are "set" define your current life.
Knowing this, if you want to change your life, it isn't really about the now. It isn't the decisions you make now. Even if you choose to go east instead of west, you will find that it was going east to get to an airport to fly west. As long as you hold these futures and those pasts, you will be going much the same way no matter what you do.
If your future is healing from some trauma, you will continue repeating that trauma, over and over and over. Maybe with different faces, but the same trauma. This is why history "seems to" repeat. And this is truly the story of many people's lives.
If your life goal is to heal from a trauma, everything else doesn't matter. As in, whatever else in your life, is in the way, it will be wiped out. You moved far away from San Diego, and all of a sudden, you find yourself back in San Diego. You may even find yourself stranded in San Diego.
(San Diego is mostly a nice place, so i am not really meaning to pick on San Diego)
When you heal your trauma, your past and your future will change. Those things in your mind that seemed to keep you stuck just disappear.
The you before was terrified to go into the water, the Giant Sea Cucumber was going to eat you. (don't discard other's fears. It is usually built up from many incidents that you may never, ever know of)
The you, after the trauma healing, is like, why was i scared of Giant Sea Cucumbers? Do those things even exist? It really just seems to go away. The whole thing. The past memories, at least the fears that were attached to them, are gone. The future is completely different. Your view of future possibilities are completely different.
You can't go back in time and fix your mistake.
The you, now, will always make the same mistake. You have to change yourself. Heal yourself. And then, that "mistake" in the past will just sorta erase itself.
This is the thing most people imagine when they think of "time travel" today. I would go back in time and fix that "one mistake". Not realizing that it was part of a much larger whole. Often, larger than your life.
This is not to say that you can't go back in time and change things. There are lots of things that are just background stuff, and you can mess with it as much as you want, and it doesn't change anything. But, that "error" you made, will seem immovable. It may happen in different ways, but it will always happen. OR! you may remove the error, but your girlfriend at that time still remembers it, and still breaks up with you, devastating you for life.
So, pay attention to these, as this is probably the trauma you are trying to heal. Or the things around it.
The way to heal it, is to go through the emotions and feel each one and mourn it, learn from it, and then forgive yourself.
You cannot go back in time and fix that one mistake, but you can heal the trauma of it, and the mistake may disappear.