Parents are too busy with their careers which leads children to seek attention by being aggressive
Parents become increasingly busy with their job and don't spend enough time with their children. They don't have time to talk to them, listen to them, know their problems and simply don't know their children enough. As a result children don't get enough attention they need and deserve so they turn to anti-social behaviour in hope it will eventually alarm the parents and remind them of their existence after being notified by the teachers, even if the kids have to deal with negative consequences afterwards.