There are many people, who over the course of their life, meet an individual who has claimed to be a Christian—who has exhibited behavior that is contrary to their particular belief, and caused other people to discount God altogether.
An enduring fact of life is that one of the leading causes of atheism is Christianity. Not that Jesus is the point of stumbling, but rather those who claim to follow him. Many people attribute the behavior of a person to the character of the God they claim to believe in. Forgetting that the Christian Gospel clearly declares that Jesus came into the world to save “sinners,” not the righteous. It is the very worst of the world that Jesus is most appealing to. The Christian life in following Jesus is frequently imperfect and lacking the basic qualities of love, patience, humility, and forgiveness. Those who are trying to follow Jesus will never be perfect in this life, although they should endeavor, constantly, to be more like Jesus in all their behavior.
It should also be understood that many people who take the name of “Christian,” are frauds. For reasons of personal financial gain or to achieve a position of authority or power, many individuals will label themselves a follower of Christ, without this fact being true.