I think a better way of framing confidence and overconfidence is your ability to feel impacted by other people around you. If someone has reached the point where other people's reactions, thoughts, feelings, seem to hit a kind of armor and gets ignored or shrugged off, he is acting like an asshole.

It is one thing to feel confident while at the same time, one feels the connection with other people. When someone uses the feeling of being "right" as a shield, it veers into asshole territory.