Why do you always "buy at the top and sell at the bottom"?

It's not because you have bad luck, but because you haven't made enough trades.

In futures trading, there is a concept called the Law of Large Numbers:

After you have made 100 trades, your win rate will infinitely approach your true level;
When you only make 10 trades, everything is a random walk.

So a true trader does not care about the profit or loss of a single trade, but only about the equity curve after 100 trades.