xīnqíng hǎo de shíhou, wēixiào shì zuìhǎo de zhuāngshì. xīnqíng bùhǎo de shíhou, wēixiào shì zuìhǎo de yǎnshì.

心情好的时候, 微笑是最好的装饰。  心情不好的时候, 微笑是最好的掩饰。

When you’re in good mood, smile is your best decoration. When you’re in bad mood, smile is your best disguise.