Decisions are best evaluated in the context in which they were made. If you, after best-effort due-diligence, concluded that a sale for $1 was an okay/good deal

Decisions are best evaluated in the context in which they were made. If you, after best-effort due-diligence, concluded that a sale for $1 was an okay/good deal, then $1 is great. It is much easier, in the long run, to be happy for the person who unlocked $499 in value on that baseball card than it is to turn inward and feel awful for the $499 you "missed out on". If you had no idea that such a thing was possible, why feel bad? I missed out on buying AMZN at IPO prices, as did most of humanity, but I don't feel bad about it. The company could have easily failed. It didn't plan to turn a profit ... ever. AirBnB's price could fall far below the IPO price in the next few months. If so, the IPO-pricing will look like genius in retrospect.