Of course everyone will regret not being able to sell coins at the right time. Although the price will increase again in the future, at least the number of assets will increase if we can sell in the right time. But for professional traders, they don't care about that. They will survive even if the value of the asset continues to decrease due to falling prices. Short-term trading is one way to cover losses. I think someone who has big assets in crypto, they can control the price movement, but if they are just a small trader, they are just following the development of the issue.