I think your friends have a huge influence on you. Lets just say if you have friends that do things that aren't exactly good of course you're going to get yourself in trouble. Another major influence in your life is you parents and family their job is to teach you morals in order to make you see the difference between right and wrong. For example if i was to do something exceptionally bad my parents wouldn't be long telling me to cope on for myself. I know people say that certain people go through this 'phase' of wild antics or whatever you'd like to call it. I'm not talking about trivial things like if you steal your Mam's really nice pair of shoes that its all downhill from there. I'm putting emphasis on the fact that if you carry on doing things that aren't acceptable in society or even in the home place and there's no one there to make you see sense of course this is going to have a serious impact on you in later life.
In saying that i think its all down to the person also. The person could have a loving family who care about him or her but they may fail to understand that whatever they are doing is wrong and is hurting the people around then i think thats a major problem.