Well, everyone has their vices be it sex, bungee jumping, skydiving, motor sports or gambling.
The problems start when their activity of choice starts to take over their life. If you took an honest look at yourself i think you would find you are addicted to something, the difference is that it's probably not doing you or anyone else any harm.
Some people like to take drugs
. So called "hard drugs" do not necessarily lead to addiction
. If someone becomes an addict
then it usually doesn't matter what they become addicted to, that is to say if they never found heroin
they would probably be addicted to alcohol
(which would almost certainly be class A and illegal if it had been discovered today and not millennia ago), or if they never found alcohol they may be addicted to cocaine
. The problem is usually systemic, they usually have issues before they become addicted and then when they find something that helps, maybe to dull the pain or forget about their worries then they could well be heading towards addiction.
This is just my opinion. I do not believe that addiction is inevitable when using drugs such as heroin, i believe there is usually other factors at play when someone becomes a heroin addict at least for my fiend and most other fiends he knows, there were "issues" before addiction took hold. I also believe that social stigma has a lot to do with heroin addiction as well as the intrinsic legal and criminal ramifications.
Then again, some people just do it for the sake of it, to get fucked up but they are quite often on self destruct mode, for whatever reason. Who knows, if we did know then we wouldn't have a problem.
Just to put things in perspective, alcohol and tobacco
are responsible for more deaths than ALL other drugs combined including prescription drugs. Also drugs such as heroin and cocaine were legal almost as long as they have been illegal, at least i think that's true anyway, not far off at least.