而且无需任何人教你如何去笑。

No one teaches you how to laugh.

youdao

在有东西值得笑时才去笑。

Smile when there's something to smile about.

youdao

生活就像挑战，所以我们很难去笑对一切。

Life is a challenge so it's hard to smile about anything.

youdao

So, if you smile at somebody, and you just hate their guts but you want to smile at them, it's--unless you're quite gifted it's difficult to fake a really good, really happy smile.

所以，你对某人微笑，你很讨厌他们，但你要对他们微笑，除非你很有天赋,很难去假笑，伪装真正的微笑。

耶鲁公开课 - 心理学导论课程节选