Not only sometimes but also most of the time taking the good profit or desired profit is hard. I think this happens only because of greediness. When an investor thinks that I will sell something at a price range and he sells the coin at that price with making some profit. But when that coin passed the predicted price range after selling then something happened to his mind that I can hold my coins for a few more days and can make more profit. As a result, if he has multiple coins then he tried to hold that coin. But not all are going the same way. Because of the holding price drops and he faces a loss. So, Every holder has to play with their brain not mind.