From 3000U to 90kU, only to give it all back in one night

I’ve seen the most regrettable account: it went from 3000U all the way to 90kU, only to give it all back in a single night. The move that truly destroyed him is one that many people repeat every day.
During the period before that, he handled almost every trade steadily—kept his positions small, took profits when they came, and was willing to wait when the market was unclear. That was how the account gradually grew. But after reaching 90kU, he began to feel that he had figured out the market. A trade that originally used only 10% of his position was later increased directly to 50%. After the first loss, he refused to stop and kept switching directions. The more he lost, the more anxious he became, and the more anxious he became, the heavier his position grew. When the market suddenly reversed in the early morning, he was still telling himself to hold on a little longer and he would recover. By daylight, only a fraction of the 90kU remained.
What truly destroyed him was never the market that night, but the sudden surge of confidence after a string of profits. Many people become cautious when losing, but lose control as soon as they make a little money, always believing that because they made money earlier, they would definitely be able to win it back later.
So after helping someone establish a profitable streak, the first thing I do is not have them increase their position size, but take away part of the profits, reduce the number of trades, and force themselves to calm down again.
Growing an account from 3000U to 90kU is difficult, but giving 90kU back may take just one moment of recklessness$BTC