There is nothing wrong in expecting good thing from this life but I think the problem starts when we believe our expectations should automatically become someone else’s responsibility. You can want the through but you still have to accept the possibility of losing the match. The ability to handle NO without feeling cheated is probably one of the clearest ways to recognize entitlement.
What most people don't know in this life is that nobody owes you anything, except your parents, so if someone is doing something or anything for you freely, he or she is doing it from a place of love or care, not because he must do it.
That is why if am rendering an assistance to someone and I have the feeling like he has started being entitled, that it's my duty to do it for him, I will withdraw immediately because it has gotten to a dangerous phase where he might want to harm you if you say that you can no longer continue doing it for him.
Truly it's a disease as the op said because it has the capacity to turn an individual to be bittered all through his life just because someone can no longer give him, what he himself cannot provide for himself, is that not stupidity in highest level?