Then you go to a staff meeting with your teaching colleagues and you hear how this same student does not learn much in other classes. They are thoughtless and inattentive. They show little creativity and no desire to participate in class discussions. They never ask questions, and are generally disengaged, bordering on rude.
But this is the same kid.
It's easy to blame the kids, but we have to acknowledge that there has to be some other variable that is influencing such a difference in behaviour.
The misbehaviour is not the problem - rather it is a symptom of a far larger problem that has more to do with forces external of the student. But if this is true, teachers, parents, schools and whole systems might have to look at their own practices and that, for the most part, is more than a little inconvenient.