The hardest thing is not to be greedy and kill yourself torment about what you have not done. And never consider a virtual profit that you have not yet recorded. Everything can be lost in an instant.
One thing I learned from books about economics is that they always teach that one should not be greedy and want to take profits at the highest price. Take profits early, earn interest rather than lose
Greed is also good, but when needed. e.g. those who greed at the last price drop have already doubled their money. But, on the other hand, those who expect more earnings should think about it a little more. Sometimes I am being greedy too. But everytime thinking this kind of will drain your wallet.
In this volatile market greed can be very dangerous because if markets fall badly then you may take years before you recover your losses. So better to keep on selling and making small profits in you like to be just short-term investors. Unless after certain level if price stabilizes then could potentially look for bigger targets.