Because I think that's actually the most satisfying life for us to live, personally, to feel that we are really making a difference somehow and we are not living just for ourselves.

我个人认为,最完满的生活，是那种，你能够感受到真正发挥了作用的生活,而不是完全地为自己而活。

普林斯顿公开课 - 人性课程节选

First of all, as I said, this class is a class about making a difference in people's lives.

首先，正如我刚才说的，这门课是关于如何改变生活。

哈佛公开课 - 幸福课课程节选