As a social worker, I specialize in high-anxiety customers who have learned in their lives to try to get what they want by maladaptive behaviors. I say “to try” because it doesn’t actually work for them. It seems like it works because many people will give in or cater to the behavior, thinking that it is somehow the best way to deal with it.
However, it is only an illusion. It may get a person off of your back momentarily, but you haven’t done anything to help him deal with his anxiety. Sadly, if this person is someone you cannot easily escape, as in a professional or family relationship, you are only creating more anxiety that you will end up dealing with later.