Worship is all about reflecting the love God gives us, back to him. If we don't think we are too bad, than we don't need much love and then we don't need to show much love to others. We reflect the love we have been given. When we, like the prodigal son realise how far we have strayed, we know the enormous love God our Father has lavished on us. We then are so grateful that we reflect an enormous amount of love to others.
So by pointing out the sins of others, all we are saying is "I am pretty good and you are not!"
Worship is about how much grace we have recieved and how much we give back. One of my mother's favourite songs said it well:
freely freely you have recieved
freely freely give,
go in my name and because you believe
others will know that I live.
Here is the link to today's sermon on Worship God with your whole life