忘其所以

wàng zì zūn dà qiě yù wàng qí suǒ yǐ de rén zǒng huì bài de yī tā hú tú

妄自尊大且欲忘其所以的人，总会败得一塌糊涂。

The people forget self-esteem and forgot all else, always fail in a complete mess.

wǒ zhǔn shì fēng le nà yàng de wàng qí suǒ yǐ

我准是疯了，那样地忘其所以。

I must have been mad to forget myself like that.