Step-by-step explanation:
We learn that some people have there problems, and want to take it out on others, or just do this for fun, since some of them do not control it, it is the lack of freedom, the person is doing this to either get attention, or to get entertainment out of bullying.
Evidence: How Roger, threw the stone, didn't care if he missed it or not, he just wanted to do something so he wouldn't get bored, but to get entertained and given attention, this tells a lot about his personality, we can easily assume that Roger is somewhere in the younger ages of 10-14, or maybe Henry and Roger got in a fight and that is what maybe triggered the actions of Roger to throw the stone at Henry, trying to potentially hurt or embaress him.