Jesus raises this very issue in the teachings found in today's gospel. Some of these teachings are well known -- turn the other cheek, love your enemies, etc. -- but they have precious few practitioners. We find it much easier to "believe in Jesus," be reasonably good and moral, and do a little charity, than we do to take up the radical commands of Jesus.
There is something downright strange about the term "Christian" coming to signify little more than beliefs. The term originally implied becoming Christ-like. It expected that people would get a glimpse of Jesus by looking at us. But the image of Jesus reflected from us often looks little like the biblical Jesus.