何必自讨苦吃何必强颜欢笑
[hé bì zì tăo kŭ chī hé bì qiáng yán huān xiào]
'Why suffer unnecessarily? Why put on a happy face?' Expresses helplessness under certain pressure, wondering why one forces to keep positive when there's no need or just wasting efforts and making troubles by oneself instead of going with the flow