The first school that children had attended is their own home and their first teachers are their parents. What values that the parents taught to their children is the first teaching they have ever learned. And in how the parents discipline their kids. I must say that parents played a big role in molding their children into a better person. What they have learned in their respective homes will come out when they are already mingling with other kids.
To be in school with other kids for the first time is new to them. Their learning in their homes will be measured as they are beginning to gain friends and be a friend to others. I have just noticed that there are kids that are not that friendly. I could say, a bully kids who love to see other kids cry and pissed off, did not show some respect to older ones and always reason out when they are corrected.
With this kind of behavior, I can say that they lack of discipline. There are lots of factors to consider why they acted that way. It can be parents, people around them and friends. Proper guidance will make them change this kind of behavior and be a better individual. And only parents can do something about this.