I can't stress how important it is to have confidence in yourself, belief or self assurance, whatever you may call it. It is essential to breathe confidence in everything you do, in many ways you are your own pillar.
Yes, we need a good support team behind us to give us that push when we make mistakes and we also need those supportive individuals to continue giving us the clarity we might lose along the way because of negative residue that we collect along our journey, but we also need our self confidence that acts without someone telling us to. Knowing who you are without hesitation, meaning, what kind of qualities you have that make up your character and personality, knowing what skills you possess that mould you into being that talented being that you are. That is where your self confidence starts to create the type of person that you are. Do not let anyone tear those gifts away from you, they take time to build and a lifetime to maintain. As long as you are certain and clear about who you are and what you want to do and why, your self confidence will not cease. In time of weakness, you'll need your self confidence such as, a break-up, betrayal, loss of employment, depression, etc. No one will be able to break you down if you know for certain who you are.
And for the record, confidence is not arrogant, it is honest, true and humble.