That's a huge question.
I'm not sure that any of us can answer it completely.
I know, for me, sometimes I have an idea of who I want to be, or maybe feel that I should be. It is easy to compare how I see myself now to the idea of who I could/should be. My ideal is, at times, overshadowed by my perceived weaknesses and faults, deficiencies and imperfections. I look at myself and see nothing special, nothing beautiful.
Then God gives me glimpses of how He sees me, and I am amazed. He uses me to do His work, to help His children, to fulfill His purposes, and I am humbled.
He picks my imperfect self up, and makes the most beautiful music with me.
This is one of the reasons why I love this video so much. It is the message that God wants all of us to hear. We all have a purpose to fulfill, a glory to reach. As we turn our lives over to Him, He can give us depth and breadth. He can take our imperfections and make us imperfectly perfect.
Through His eyes we are beautiful. With His hands, we can become something more than we are alone.