I have this recurring fantasy of going back in my own timeline to get a second chance at things. There's a lot of crap from my teens and twenties that I'd like to get a do-over for, and things that I figured out later in life that I'd love to have gotten started on earlier. I go through these scenarios for different points that I could jump back into my life, thinking about what possibilities I'd have if I jumped into me circa 1997, for example, versus me circa 2001. The amount of knowledge I'd be able to carry with me is a huge wildcard, and if I were able to make changes, I'd also need some way of guaranteeing I'd still be able to end up with my wife and build relationships with the tiny group of close friends I have today. I'm a completely different person today than I was then (though overall I'd say a much better one,) so it's hard to say how things would develop.
Honestly, it's a pretty stupid rabbit hole to fall into. I'm doing better right now than I have at any point in my life and going back would force me to suffer through some hardships until I cheated my way into riches using my future-knowledge. It's likely my perfectionism that forces me to constantly consider all the ways things could have gone better, so I lay awake at night thinking about that instead of considering that my life actually turned out pretty fucking good and going to sleep.
I do a reasonable job of living in the present, until moments like this hit. I'd love to give up this dwelling on the past and exchange it for looking forward to the future, which unfortunately seems to be in short supply for me lately.