Not learning how to invest my money in early 20’s instead of spending it all on crap I didn’t need and not having the foresight to know I could have been in a much better position today financially had I just put my money away in the market rather than lighting it on fire with stupid material purchases that are in a landfill somewhere today.

If you are young and have an income stream, do your future self a favor and invest in a diversified fund as much as you can and a 401k and don’t touch it until you’re ready to retire. Compound growth is insane.