冰冻三尺非一日之寒
[bīng dòng sān chĭ fēi yī rì zhī hán]
This Chinese proverb literally means that 'three feet of ice does not freeze in one day,' it implies deep-seated problems did not arise overnight; they result from accumulating over time - often referring to situations such as deteriorating relations or personal issues developed after series of misunderstandings or conflicts.