For some, it is easier than atonement. Religious guilt is usually an end in itself. I convict myself of a wrong doing and I punish myself with a little guilt. And that's the end of it. Having punished myself with a few twinges of conscience, I feel entitled to a little burst of self righteousness.
Guilt is almost always a self serving emotion.
Guilt demands no response other than punishment and often times we regard our guilty feelings themselves as punishment enough. Mature religion ought to awaken us to the ways in which we could or should respond to the moral demands of our world, not merely give us permission to assume a holier than thou attitude after wallowing in a little self induced guilt. Yom Kippur is the Day of Atonement. Jews all over the world gather on this day to fast, to pray and to confess their sins before God. But the emphasis is placed not on guilt, but rather on response-ability.