I look at it as Confidence + Negligence = Arrogance. You can be confident but when you neglect what could go wrong, you're just being a jerk. When you take care of the details (practice, train, press yourself to be better and proficient at what you do, it goes a long way toward removing negligence/doubt and building confidence. It affords you the humility that becomes the deciding factor in keeping you confident but grounded. 2 fighters can have the same amount of confidence, but the one that believes he still has reason to be cautious avoids crossing over into arrogance. A man possesses confidence where as arrogance possesses the man.