maybe u wrote the wrong word,is it 恨铁不成钢？it express that hope u go-ahead。unsatisfactory with the person who don‘t pay the effort。

原话是“恨铁不成钢”，形容对所期望的人不争气，不上进感到不满，急切地希望他变好。 恨爹不成刚，是从这句话改过来的。有个小孩闯了大祸，然后对别人说“知道我爹是谁吗，我爹是李刚”。这句话现在通常用来讽刺特权阶级。

The original expression is "恨铁不成钢" means:" Expecting iron to become steel". Usually used to express a father wish his son/daughter to be better off. In 2010 there is a very famous issue, one rich guy drive a car and hit a girl to death, when police come to contol this guy, he shoult" My father is Li Gang (李刚)“ （his father is an officer in police office）. So People creat this new express"恨爹不成刚" means: Expect my father to be Li Gang. This is a joke aims to criticize the government officers do not give good education to their children.

表示对某人很失望。 You feel very disappointed about someone.

是恨铁不成钢 不是恨爹