Why doesn't the Pilferer think of themselves as a thief?. Sociology

They think because they have stolen from a department store that is worth millions, and the item took for personal reasons, and they believe it is not cheating. They might even offer to pay for the thing once they have been caught and arrested. They feel humiliated and can't understand why they might go to jail. Their significant others do not think they are a thief either. Even though they have stolen, and they do not believe they are a thief, are, as no matter how much the item is worth, they are still a thief.