恨如饮鸠
[hèn rú yĭn jiū]
'恨如饮鸠' can be interpreted as 'Hatred Like Drinking Poison.' It expresses that hatred (or other deep, painful emotions) might harm oneself like slowly drinking poison. There's also connotation from classic literature where '鸩' (poisonous bird representing a slow, harmful process) is sometimes seen as metaphor for negative things that destroy one over time.