This proverb means that children don't know the real intentions of their parents.
As well as almost of the people,I didn't know the real intentions of my parents. So I had had some grudges against my parents about having been scolded.
But I recently regret that I didn't obey them. If I obeied them,I might be...now.
Anyway,it's too late for regrets.
I'm going to become a father in September. I think I'll explain the reason why my children are scolded when I have to scold them. And I hope that they will become to consider the reason why they are scolded.