The nature of teaching is to teach. Students are either motivated to learn or they're not. Some students will do well whether they want to or not. Students are adolescents and they are biologically programmed, to one extent or another, to resist demands made of them. Children and adolescents are also biologically programmed, to one extent or another, to be egotistical ("If I don't know how this benefits me, I see no point in doing it."). They also naturally lack, to one extent or another, executive functioning skills that allow them to think ahead or to consider consequences. That's why babies cry, children lie, and adolescents are drama queens. It's just how they are. Now, throw in some good old fashioned family drama/trauma on top of that. And the teacher's job is to teach them, even when they don't want it, and even when they resist all demands, and even when they don't seem to care about anything but themselves.

A lot of us here have "headache students," but you'll notice that the vast majority of our complaints have less to do with students and more to do with management and bureaucracy. You have to understand how children are, and accept that radically and unconditionally, before you can teach.