the children learn certain traits from there parents, violent parents, generally produce violent children. Children are very impressionable, and if they see you doing something that they are told not to do, like violence, Drugs, alcohol or smoking or anything like that, then they will naturally try and rebel against you, you've got to practice what you preach, so to say. If you don't stand by your word, children will push you to see how far you will go, they're naturally rebelious, and they will try to break every boundary you set, unless you teach them respect.