those who always buy when the price goes up usually get FOMO buying and those who usually sell when the price goes down usually get FOMO selling.  So broadly speaking, these two activities are said to be FOMO, and that happens because the person does not have the ability to manage the information that enters their mind.   

for beginners, make it a habit to find out in advance what to buy, and don't buy or sell out of fear.  You are just wasting your money and time if you buy carelessly, buying bitcoins for beginners is highly recommended.