A person who is arrogant speaks authoritatively but tries to weasel out of justifying their statements by using logical fallacies, deflecting attention to others or other matters, or bullshitting.

There's also a general attitude component that seems pretty common. A confident person doesn't need to put their ego on display for everyone, because they believe their positions have a firm foundation in data or fact to stand on. An arrogant person will tend to engage in a lot of bluster and undeserved self-promotion to distract from the lack of quality of their ideas.

Both confident and arrogant people can be right and wrong at various times. I'd like to believe the confident person is generally more right than the arrogant person, but that isn't necessarily the case. Having worked for and with both types of people, I would rather work for someone confident, even if there was an arrogant person who was right more often. The stress and disgust that comes with working with arrogant people just isn't worth it to me.

You need confidence to assume your choices, sell your ideas, and take risks. You need to avoid arrogance to avoid mistakes, learn, and build a healthy team