"Happiness is a fleeting thing, Sally, but I think that a man can come closer to it by directing the forces of his life to a single goal that he believes in. And I think that a man's personal search for happiness is not really a selfish thing, either, because by achieving happiness himself, he can help others to find it. Does that make sense to you?"
January 1, 1970
https://en.wikiquote.org/wiki/You're_a_Good_Man%2C_Charlie_Brown