This is the best psychological explanation for "earn and run, lose and hold (earn small, lose big)".

There are two kinds of pain in trading, one is the pain of losing profits, and the other is the pain of losses. When you see profits, your subconscious will make you want to close the position so that you won't have to face the pain of losing profits; when you are losing, the subconscious will make you hold the position longer, otherwise you will immediately have to face the pain of bearing losses. As long as you don't close the position, there is still hope. The purpose of the subconscious is simple, just to make you avoid pain.
However, this is precisely the biggest psychological barrier that hinders you from becoming an excellent trader. The significant difference between ordinary retail investors and outstanding traders lies in the ability to make small profits and incur large losses, or make significant profits and incur small losses.