Christians are also good at rationalizing their sins. God is reduced to a vague concept of love. And their spiritual lives disintegrate. All Christians are sinners, so it's easy for us to get offended. A special danger is hypocrisy - we present ourselves one way, then act another.
Christians can also be cruel to each other.
We are told warm platitudes that may not measure up to reality. Christianity is just one of thousands of religions, and it's not very scientific. They get out of the habit. Sickness may keep you from church for a few weeks. You're not a pagan - you watch a television preacher.