Why do some people see themselves as superior to others when they actually arent?

putting aside the people who for one reason or another maybe ARE superior to other people, like high intellect or a lifetime of righteous deeds and just look at the people who actually ARENT better then the people they look down on. how is ti that someone with no special talent or skill ,just ordinary or below ordinary intellect and nothing to show can think there better then other people. my boss at work likes to lord it over everyone there and i am one of his favorite people to exhibit his insolence to for whatever reason. he likes to make people feel as if they could never achieve what he has (being the manager of a small cabinet shop his dad owns) and makes fun of anyone's problems as if we all deserve anything that comes to us because we are some kind of lower cl. is this maybe a mental disorder of some sort he has going on? why are people like that and how can they perceive themselves as better then people who they aren't "better" than.