Do human beings have good will from the beginning when they were born? Babies are drinking mother's milk and crying during midnight without thinking about others. Surviving is more important than good will for the babies.
As people grow as a social animal they will learn the importance of good will because if they were selfish, they will be inhibited from the society. Then they become to do good things for others despite of self-sacrifice. With their growth, people will acquire good will i.e. altruism.
It is difficult to sustain good will because human beings are naturally egoistic, sometime good will falls into hypocrisy. Good will is sustainable if egoistic action without self-sacrifice will be the same with altruism action.
I think, Ego/Altruism i.e. Win-Win relationship will be ideal solution for happiness and peace of human beings.