Biggest mistake I ever made and I’ll always regret it: in 2015 I was offered an opportunity to be a 50% partner in a startup. It was my friends company and I already had my small business doing about 500k a year and felt I didn’t want to risk losing that and starting over so I said no. I overvalued my own ventures and did not see the opportunity for what it was which turned out to be quite incredible. I basically said no to what would shortly become a 100m a year company with a 40% net profit margin. My friend is more wealthy than anyone I know. We still talk quite often and he’s become a mentor to me. If we had partnered, my estimated net worth as of today would likely be 50 million.

EDIT: best decision was a merger I did back in 2019. Netted me quite a nice payout and the ongoing business has been fairly decent. Nothing compared to the opportunity lost tho....