A lot of fun things aren't addictive. For example, I've done a lot of sports. I enjoy them. I don't suffer withdrawal if I stop doing them, and I don't feel a compulsion to start doing them. Indeed, I need to motivate myself to do them.
A lot of addictive things aren't fun. A gambler might be miserable but CAN'T stop. Likewise, there were a lot of time-wasting games in the 2010s which no one enjoyed playing, but which were very hard to stop.
A popular model was:
- Click on things to gather points / resources / etc. which you can trade in to be able to do more.
- You have a constant feeling of progress. There is often exponential growth of some kind of points / diamonds / etc. as you can trade them in for things which produce more.
- There is real-world time involved. For example, plants might grow in 8 hours, and whither in 24. You need to log in periodically or you lose them. There might be weekly rewards, which are one-shot (if you don't get one some week, you lose it forever).
- There is an element of randomness on rewards (treasure boxes) and determinism on punishments (if you've failed to log in one week, you lose that reward forever).
This was well-studied. Similar techniques are used by shopping vendors to get people to buy, employers to get people to work, etc. We've gotten really good at making things addictive.
Right now, there's a similar thing happening with hate and polarization. People have a need to follow stories which often have no effect on their lives (in some cases, are statistical anomalies), but which serve to scare. We're wired to follow fear. That's a lot more effective than the 2010 model, and makes people hate each other.
A lot of drugs create a dependence too, without being fun.