I know a lot about addiction. Social media is not physically addictive, but anything can be a habit. Caffeine is physically addictive. People will say they have a workout addiction, too, but I don't think anything that delivers a natural high is an addiction. Addiction is when chemicals fool your brain into thinking it needs different stuff than normal. You're not addicted to oxygen, food, etc. Those are needs. When something substitutes itself for eating, like meth, you're addicted. When something becomes a physical need beyond the natural stuff like food and water, it's an addiction. Now, we don't always talk about medical treatments in those terms -- we don't need to -- but you can become physically dependent on medical treatment.

Stuff that makes you happy is just stuff that makes you happy. Social interaction can be disordered. When it is, we talk about it in different terms. We say someone is a narcissist, not that they're addicted to attention, except metaphorically. Typically, it's avoiding social interaction, rather than relishing it, that is disordered. That's because it's as much a need of humans as food and water. Yet the relationship between humans and interaction can be as disordered as the relationship between a bulimic and food.