problem is when you are thinking to sell it quickly the emotions are more higher in your mind but if you do it for long time then no other problems will came to you because you don't much need to carry about them and it really helpful to get a huge profit when you are holding it for long time
But if you wait too long and miss the optimal opportunity (price) to sell then people tend to hold on hoping the price will go up. Which results in people hanging on until the next bull run or prematurely sell cheap.