The right thing to do individually or collectively is to maximize, act in a way that maximizes the overall level of happiness.

于公于私，最正确的选择都该是,即为全方位地最大化地提升幸福。

耶鲁公开课 - 公正课程节选

But ultimately, the best way, the optimal way spreading happiness is to work on your own happiness, because then you are leading by example.

但最好的方法，传播快乐的最佳方法是努力争取自己的快乐，因为那时你就成为榜样。

哈佛公开课 - 幸福课课程节选