While it‘s generally wise to focus on the things one can change, I‘m curious what things in your life you regret.
I don't mean things that you would regret theoretically if you thought about them. I mean things that you actually find yourself regretting every now and then in spite of yourself. Things that your mind gravitates back to in moments of serenity that give you a sense of regret or sadness about something you did or didn't do, even though it was years or decades ago.