If you are happy, and work on your happiness, you are contributing indirectly to other people's happiness, just like the baby who laughed last time-- made you laugh.

你快乐并努力争取快乐，就是间直接对他人的快乐作出贡献，就像上次大笑的婴儿，把你们逗笑。

哈佛公开课 - 幸福课课程节选

Happiness is when you find balance in your life,

幸福是找到生活的平衡，

寻找幸福 - SpeakingMax英语口语达人

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

These topics are sleep, laughter, and religion, mental illness, two lectures on madness, what can go wrong in your minds, and a last lecture on happiness.

这些话题包括,睡眠，笑，宗教，精神疾病，我们会用两节课讲精神病，也就是你的脑子会出什么毛病，最后一节课讲幸福。

耶鲁公开课 - 心理学导论课程节选

So you may want to spread happiness, through your word.

你也许想传播快乐，通过你的言话。

哈佛公开课 - 幸福课课程节选