It is only when the whole of Humanity has attained happiness that the individual can hope to become permanently happy for the individual is an inseparable part of the Whole.
Food for thought and a warning
He who is thoroughly imbued with altruistic feelings, with a willingness to forget self, and readiness to help his neighbour to carry the burden of life, is to become the object of ridicule, slander, and vilification. It is one of the most difficult yet necessary things in life to learn to disdain. Disdain protects and crushes.