I don't see how a person can't love God and other people unconditionally. Besides, think of how your parents raised you. Today, you might be doing something because you know that it's important or the right thing to do. But weren't there times when you were younger where your mother or father or guardian had to tell you to do the right thing?

In this capacity, God is just another parent. Our parents tell us it's important to eat broccoli when we're little, and when we're older, we understand why it's important, and we (hopefully) do it. When we have a fight with a friend, our parents teach us the importance of apologizing, and as we grow older, it becomes important to us on our own. And in a religious context, it's important to love others unconditionally. And so we learn, as we grow older, what that means, why it's important, and how to do that.