When we were small, our parents were godlike to us. They had all power over us. We probably thought they had all power in the world.
This experience imprinted on us, and subconsciously we assume that God is like our parents. Better said, we project our parents onto God, and so expect God to treat us and the world like they did.

But nobody’s parents are perfect. Most lose their tempers or criticize their children unfairly from time to time. Many sometimes place unreasonable demands on their children, or punish them harshly, or control them with shame. Some parents abuse or neglect their children.
And so we may believe God watches over us with a critical eye and is never satisfied with anything we do. Or we may assume God is just waiting to turn his back on us when we screw up. Or we may think we need to work hard to earn God’s favor and love. Or we may figure that no matter what we do God’s not going to care about us anyway, and so we give up trying.
But God’s more like the perfect parent none of us ever had. He wants to see us grow up well. He never loses his temper or patience with us. He knows there is sometimes pain and difficulty in our lives, and he wants us to turn to him for comfort and encouragement through it so he can help us become stronger and more loving. He knows we make mistakes and sometimes even deliberately do the wrong thing, but he won’t turn his back on us, or shame us, or punish us no matter how bad it was.
At our cores, we all want to be loved. God wants to love us. Our fears that God will let us down in the way our parents did gets in the way of us simply accepting that love. We have to keep working on our relationship with God and over time come to see him as he truly is before we can simply accept the love he has for us.
If you are a parent, consider what a service to your children it would be if you modeled your parenting after the way God loves. Not only would your children feel your love for them more strongly, but it would make their image of God be so much closer to who he really is. It might help them more readily accept God into their lives.
When I turned to God, he showed me that love paves the way, and that to follow him all I have to do is hold up my hand for him to grasp.