God is my Father, what a thought! I am a child of God not by my choice but because He has chosen me. That is a very humbling thought, because I know what kind of thoughts that I entertain throughout the day and I know my actions are so often contrary to the fact that I could be one of God's children.
The doctrine of adoption is a wonderful doctrine that should stir us to love the Father and worship him without any reservations whatsoever, however our sinful flesh gets in the way so much of the time. Immersing ourselves in the doctrine of adoption would help to clear away the fog and allow us a clearer vision of God's love toward us as sons of the most high God.
If you're looking for a tool to help in that immersion, please check out Children Of The Living God by Sinclair Ferguson. It's a relatively small book that makes a huge impact and will definitely bring into focus the love of the Father toward his sinful sons and will help familiarize you with the wonderful doctrine of adoption.