Addiction is generally defined as not being able to stop an activity that rewards you in someway despite the consequences. With drugs like heroin it's important

Addiction is generally defined as not being able to stop an activity that rewards you in someway despite the consequences. With drugs like heroin it's important to note the difference between chemical dependance and addiction. Chemical dependance can certainly cause addiction, but plenty of heroin addicts are (citation needed but I'm pretty sure) staying addicts because they want the high - which is the same principle as how people get addicted to gambling, or to weed (a drug that doesn't cause any physical dependance) - not because they are trying to keep withdrawal symptoms away. Of course, plenty of addicts do at some point want to quit and at that point the dependance can keep them addicted. Arguably the line between "addiction" and "lack of discipline" is subjective and arbitrary. It's possible to be a heroin addict, decide to never do it again, and... just do it. I've no personal experience but know it must be hell to try and do that, but it's absolutely possible. And former addicts, who no longer have any traces of the drug in their body, who have got past all the withdrawal... often relapse, for what you could call "lack of discipline". Equally, many people are addicted to gambling in ways that leave them losing all their savings, or addicted to weed in a way that they get nothing done in life because they're getting stoned all the time, or... For me, the line would be drawn based on how hard it would be to give it up, and how much damage is being done. If you're just annoyed that you spend too much time browsing the web, it probably shouldn't be called addiction. If you spend 95% of your time in the office browsing the web, and are concious that this is causing major problems for you, but still can't bring yourself to stop... addiction seems fitting.