Here is a quote by Eugene Peterson on the value of seeing people as sinners. I think that this can apply to parenting as well. We need to not be shocked, mad, dismayed, or frustrated when our kids sin. We just need to remember that they are, in fact, sinners and then be delighted when they act nicely!
"The word sinner is a theological designation. It is essential to insist on this. It is not a moralistic judgement. It is not a word that places humans somewhere along a continuum ranging from angel to ape, assessing them as relatively 'good' or 'bad.' It designates humans in relation to God and sees them as separated from God. Sinner means something is awry between humans and God. In that state people may be wicked, unhappy anxious, and poor. Or, they may be virtuous, happy and affluent. Those items are not part of the judgment. The theological fact is that humans are not close to God and are not serving God. To see a person a sinner then, is not to see him or her as hypocritical, disgusting, or evil. Most sinners are very nice people. To call a man a sinner is not a blast at his manners or his morals. It is a theological belief that the thing that matters most to him is forgiveness and grace.