Is there any point in telling someone not to start? people will try any drug if they've made the decision to do so, heroin isn't life ruining, its all down to the user. As far as i can see, being generally an addictive type of personality is the worst part. and its quite hard to get addicted if you're not say, a smoker or generally addictive person.
I've managed to kick a "habit" for less of a better word. only difference in my life now is that I use needles, no big deal really. It's all just getting over stigma