"So, throughout life, our worst weaknesses and meannesses are usually committed for the sake of the people whom we despise."
This quote can refer to how Pip has become something completely opposite from himself for someone he despises, in this case Estella. He is now treating Joe in a way that he should not be treated for the sake of Estella. He has become corrupted by the money and status he has gained and has forgotten where has come from to get this far. He has become weak for a love he himself is not even sure is there.