I wanted to give you guys a little insight into the problem. I had a heroin addiction for three and a half years, and finally kicked all chems from my life about 18 months ago. Friends often asked my why people would use heroin enough to develop an addiction, and all I could say was "don't knock it until you've tried it" because, as you say, it is impossible to know without being there yourself. Heroin feels great. I won't go into a long a detailed description of how and why it feels so good, but this is the main problem trying to explain usage problems to other people. You want to use it because it feels unreal. You don't wake up going "oh no, I'll have to score today to feed my beastly horrible addiction", you wake up and say "i'm gonna get some smack today and have it because it feels so fucking good, and I can't wait". It's hard to explain to somebody who has never used just how good it feels. And that's the problem of the addiction, you certainly aren't suffering while you're on the nod. You like it, and use it more and more until you physically need it. People seem to have this false idea that users are almost "tricked" into habits, but believe me, it's all self-inflicted. Once the heroin takes over though, you are a slave to it, and not the other way around. It affects your thinking, your emotions, your logic, your judgment, everything. Your life suddenly focuses on heroin and not the things that are actually important in life. This is much like gaming addiction, in that the more you play and play, the bigger a part of your life it becomes, and due to the nature of time, other facets of your life must suffer to make room for the addiction. Unlike heroin however, gaming does not have a real-world reward (at least on smack you are high). Also, heroin addiction, like smoking, revolves around routine. Just like how the ex-smoker gets hooked on the physicality of smoking, (rolling a smoke/ using the lighter/ ashing the cigarette/ hand-mouth movements) the junkie gets hooked on the routine also, or as others have called it, "the feel of the steel" ie: mixing up in the spoon, preparing the drug, injecting the drug. Gaming also has similar routines, getting a mountain dew, getting smokes, snacks, whatever ready for a nights solid gaming, sitting in front of the computer, etc. It seems to me all addictions have these routines in common, almost like a ceremony before or during the act. Breaking those routines is as (and for some people, moreso)important as kicking the addiction itself.
I recently made some comments on a discussion about internet gaming addiction compared to my own heroin addiction here on slashdot. It seems a lot of people had some questions and opinions regarding the more serious types of addiction, so I though i'd post my comment here. Have a read, and if you like, say something.