Confidence can take you a long way, but don't mistake it for arrogance -- one seeks to lift others up from a place of satisfaction with yourself, and the other seeks to diminish others because of insecurity. In this video, Aaron from I Am Alpha M describes the difference beautifully.
It may seem obvious at the outset, but it's often the most arrogant people who defend themselves by saying they're just more self-confident than others. Much like the difference between assertiveness and aggressiveness and compassion versus niceness, confidence is internal, and arrogance is external. Aaron explains that confidence is something in you, a belief in your skills and abilities, and a trust in yourself. Arrogance on the other hand rears its ugly head when people try to diminish the skills and abilities of others, usually to convince the world of their own status and push others into the background.
The video above goes into more detail, and the whole four minutes is worth a watch. If you don't have time to watch it, check out the link below for a written semi-transcript of what he says.
Confident or Arrogant | Which One Are You? [I Am Alpha M]