When I was a youngster, the way this topic was explained to me was individuals who have a misguided sense of entitlement generally fall into either of two categories: those who "had nothing" in their early years, and those who had "everything handed to them on a silver platter." Individuals in both categories seem to have the idea that the world and everybody in it "owes them something." The general viewpoint is "what's mine is mine... what's yours is mine... and everything I want, also, is mine."
I have known numerous people in the first category, and fewer in the latter. I have known people in the first category who, through their adult lives, lie, cheat, and steal with a sense of entitlement in mind-- even though they did not earn something, they fully believe they deserve it.
Those in the second category are equally difficult to deal with. As they were given everything when they were young, they go through their adult lives fully believing they are entitled to everything they want.
The one factor both have in common is a misguided sense of entitlement is often harmful and damaging to someone else. Whether they are attempting to claim something that is not rightfully theirs by cheating on their income taxes to get more money, infringing on another person's rights, or stealing from stores, there is probably no instance in which a misguided sense of entitlement does not harm someone. It seems no different than a bad little child who steals his friend's toy simply because he wants it for himself-- although it is on a much larger scale.