Disruptive behaviour is usually due to external factors I imagine - are you struggling with your parents' divorce, are you over tired from gaming all night, are you on drugs, suffering teen angst, ...

Disruption because the class is above or below your level is also, to some extent, uncontrollable by the teacher - they have 30 kids (typically in UK) to cater to.

Teachers can be entertaining, but that isn't always conducive to the subject matter.