I'm not talking about hindsight and wishing you invested in Apple 25 years ago or you shoulda bought a 72 911S new. I'm talking about real deals that were actually offered to you and you said "meh...nahhhh."
My misssed opportunity? Around 1986 a friend of mine invited my then wife and I, along with 10-15 other couples, to a party. He was seeking 12 investors at $10K eqach so he could build a prototype product he wanted to develop.
I didn't have $10K to risk and coupled with the fact this friend had run more than one of his pipe dream companies into the ground financially, I politely declined. Nice guy but he wasn't generally regarded as a primo business man.
But some of our social group took a leap of faith and ponied up. A few even invested $20K.
Three years later when the company was bought out by a larger investment group, the return on the original $10K was nearly $1 million.
The friend? Freddy Carl. The Company? Viking Range.