I was reading this morning in Keller's book. He is talking about the misnomer that Christians should somehow be kinder, better, less prone to immaturity and moral failings than the rest of society. He said that kind of thinking is based upon the idea that we somehow get 'cleaned up' and then come to Christ - kind of opposite to what the gospel actually is.
Here is an excerpt I found interesting:
"Good character is largely attributable to a loving, safe and stable family and social environment - conditions for which we were not responsible. Many have had instead an unstable family background, poor role models, and a history of tragedy and disappointment. As a result, they are burdened with deep insecurities, hypersensitivity, and a lack of self-confidence. They may struggle with uncontrolled anger, shyness, addictions, and other difficulties as a result.
Now imagine that someone with a very broken past becomes a Christian and her character improves significantly over what it was. Nevertheless, she still may be less secure and self-disciplined than someone who is so well adjusted that she feels no particular need for religious affiliation at all. Suppose you meet both of these women the same week. Unless you know the starting points and life journeys of each woman, you could easily conclude that Christianity isn't worth much, and that Christians are inconsistent with their own standards."