Damn, the director is a great guy. He knows the moral lesson of the saying "The axe forgets, the tree remembers" which many parents usually aren't aware of. One outburst will be forgotten but to many children out there inluding me, we don't forget the emotional damage of moments like those whilst it's just tuesday to them and is forgotten within the week. It's very important to take sayings like these to heart to be a better person even if you don't plan on raising children. Stuff like this is why media literacy is so important and finding good media to consume is also important.
(I wonder if theres a korean equivalent, gonna search that later)