From elementary school all the way up through high school, students have this "can't wait to get out" attitude. This also coincides with kids acting up in school. Throughout the younger years it isn't so bad because there's not that much of a serious disturbance that a twelve year old kid can make. However, as kids get older and earn more privileges and responsibilities, the kids that are troublemakers are a bigger problem.
Such kids can be a constant disruption to their class. Teachers shouldn't have to put up with a student constantly causing a disturbance in the middle of their teaching…