Kids don’t act up because everything is rosy, but sometimes the problem has nothing to do with the parents and is beyond their help.
If a child is kicked out, either he will accept it and start living his own life that doesn’t involve his family, or he will feel rejected and become angry or depressed. If he becomes depressed, he will give up, and if he becomes angry he may just go out and do every bad thing he can think of. And if he does that, he may be ashamed to return even if he wants to.