The story popularized the phrase "goody two-shoes", often used to describe an excessively virtuous person, a do-gooder (https://en.wikipedia.org/wiki/The_History_of_Little_Goody_Two-Shoes).
When I perpetually find my deepest satisfaction from someone or something other than God, it is a sign I don't know God.
It is possible to acknowledge the existence of God while not truly knowing Him. This statement should make any Christian pause and think. If it doesn't, then pride has raised its ugly head. I should always consider this, "Do I really know God?" I'm solid in foundational issues, but it's the details that will always be foggy, partially understood, never fully known --until we stand face to face with the living God . Even then, it will take all of eternity to learn about Him. He's that big.
If we're going to address the subject of a sinful nature, we have to go back to Adam and the original sin. Adam's choice caused God to banish him and Eve from the garden and that was only the beginning of humanity's isolation from God. Sin did not merely change extermal conditions--something was terribly altered within us.
Paul speaks of sin as "spiritual death". He quotes old testament scripture: