The philosophical definition just opens up bigger cans of worms that can't be adequately addressed in an HN thread, and have been debated for thousands of years: what is "good"? Perhaps we need a moral framework to answer that, but then, what are morals? "You can't have good without optimism" is a declaration that has to be contextualized, and is far from universal.

I suspect answers couched in terms of individualism will always sound inadequate to questions that are inherently collectivist, such as why people do things "for the greater good" detrimental to their own well-being.