Some people have this habit of claiming that their boss’ boss is their boss, too. Their boss’ boss could be the head of their department but that doesn’t make him their boss. A person’s immediate superior is his boss; not his boss’ boss. This is just to explain that a person wants to associate himself with someone who’s more powerful and more influential but doing so is rude and unfair to one’s immediate superior.
My boss’ boss is the president of the company but that doesn’t make him my boss because I get orders from my boss and he’s the one rating my performance. In addition, I respect and I have faith in my boss so there’s no need for me to claim that his boss is also my boss.