love

I was at church this morning. Somehow a service ostensibly about God's amazing love left me feeling a worm. Can this be right?
I know I am human. I know I am not God. I know I get things wrong, and do what I want rather than what God wants. So, yes, I am a sinner (as is everyone else).
No, I don't understand why God loves me. I just know he does.
Come to that, I don't understand what my husband or friends see in me that allows them to love me either, but I know they do. I have no idea why. But I know that they do love me, and I accept this - not as my right, but as an undeserved gift.
I don't go on about it everytime I see them, telling them that I don't deserve their love and how I'm an awful person. I think that would be rather insulting - it's basically telling them I know better than they do, and they are wasting their love. They have given me their love as a free gift, and I accept it as such, even if I don't understand it. And then, maybe I move beyond that to realising I AM loveable, despite what I might think of myself.
So why is it different with God? Why do we have to keep doing the "I'm a terrible sinner" stuff? Why don't we move past that to saying "God loves me, I don't understand why, but he does" and then live in the light of that love, allowing it to redefine who we are? Or is that too threatening?