> When you mess up - which isn't just losing USD, it is underperforming the market's usually-positive return - there is someone out there on the other side of the trade who is buying what you sold and selling what you bought. When you underperform the market, they overperform the market by exactly as much.

If I trade profitably but making below market returns, the notional someone else who is taking the opposite sides of my trades is not outperforming the market by as much as I am underperforming, they are losing money and, thereby, underperforming even worse than I am.

There's obviously people in the market overperforming, but it's not someone taking the opposite of my positions that is doing it.