Teachers are under a lot of pressure to ensure that pupils perform well at school. This is not just in the day to day classroom environment but also in terms of exams, which appear to be starting earlier and earlier.
One of the main difficulties a teacher will have is classroom control. Having a number of disruptive pupil in a class can send the rest of the class in to disarray and make a relatively simple task almost unachievable.
If you have a child or a number of children that are constantly disruptive, you need to try and find out why. It may be that they have issues at home that are being brought in to the classroom or it could be that they find the work being set for them too hard or even too easy. Research shows bright children can get easily bored with work that is not challenging and therefore will play up and become disruptive.