I walked away from a unicorn, a few years ago. If I had stayed - and somehow survived the effects it was having on my mental health - I might actually be a millionaire now.

Instead, I bought a fee thousand dollars worth of shares - only what I could afford. They IPOed at 10x, and I made a down payment on a house.

But that was a rare case: I had some extra savings, the company was clearly succeeding with clear intent to IPO. And even so, I had to wait four years for a payoff.