By volunteering in wM's classroom.
I was pleasantly surprised at how attentive and well mannered many of the children are. I was also horrified as I saw some behaviours that, left unchecked, are likely to lead to bullying. (And yes, I informed the teacher.)
And then there was the little girl who picked up the wooden ruler and raised it as if to hit one of her classmates. While she was reprimanded for the behaviour, my heart sank for her. I can only imagine how she learned about that.