I think what you want to say here is to buy low and sell high. Of course buying in high prices and selling them when its low is a very obvious loss. If I had 2 bitcoins, I probably did not sold it when it was in its 20000 dollar mark. I would expect more even just a little pump. But I would have sell it if I saw bitcoin is slowly dumping. I probably would have sold it at 18000 dollars.