The miserable man must have his defect causes the misery.（可憐之人必有可恨之處 ）

A fair face may hide a foul heart. （人不可貌相。）

A man knows his companion in a long journey and a little inn. 
（路遙知馬力，日久見人心。）

Bite the hand that feeds one. 恩將仇報。

By doing we learn. 經一事，長一智。

A little neglect may breed great mischief. 小不忍則亂大謀。

A good medicine tastes bitter. 良藥苦口，忠言逆耳。

A good fame is better than a good face. 好的名望勝於好的相貌。