When bitcoin is at low price we are afraid to buy because we think it's going to dump more but when its price goes up we don't know where to buy at the proper price. FOMO is difficult to control, what I do is when I already bought it at somewhere at a high price I avoid looking at my price tracker app. And I think people that are most affected by this feeling is those who can only buy using their extra money. They won't afford to buy again if price goes down more.