恨鐵不成鋼 [ㄏㄣˋ ㄊㄧㄝˇ ㄅㄨˋ ㄔㄥˊ ㄍㄤ; hen4 tie3 bu4 cheng2 gang1] lit. to hate iron for not becoming steel to feel resentful towards sb for failing to meet expectations and impatient to see improvement (idiom) ◄ ►