There is a deep gap between a wrongdoing and the conscience of your fault.
The first one entails a series of facts and judgments which cannot be reduced only to the wrongdoer, though he is the most important protagonist. On the contrary, because he is the most important factor in producing the wrongdoing, he consumes his action in that wrongdoing and has a pale contribution into the next steps after its end.
He leaves out the scene on behalf of his action that becomes the subject matter of outer reflections to him, even if he himself thinks of it.
Therefore, the guilty conscience, where the wrongdoer is the main agent in a continual manner, cannot directly derive as a direct consequence of his wrong action.
Thus, the guilty conscience has other sources than the action itself: the religious education, the social reprobation, the inclination for self victimization, etc.
Such discordance is responsible for the easy disappearance of the guilty conscience. The wrongdoer is not accustomed to prolong his responsibility more than the duration of his wrong act.
The discourses about an everlasting fault and eternal penalties do not succeed over a wrongdoer, if they are not formerly prepared by his moral and religious education. Otherwise, they cannot fake the fact that human beings feel just a short-time responsibility.