A lack of humility often resembles arrogance while that's almost always a byproduct of fear and insecurity. Being open about your own weaknesses allows others to understand where they can help. Arrogance on any team is detrimental as it breeds resentment, stifles communication. Too much humility risks teetering into meekness which in turn can lead to inaction. Great leaders will defer until they've squeezed every ounce of potential out of their team but won't hesitate to assume control when required.