Dopamine: More Than Pleasure, The Secret is the Anticipation of a Reward - LiveInnovation.org

"The reason for it is because the uncertainty of receiving the reward creates a much greater expectation and therefore dopamine production."

https://liveinnovation.org/dopamine-more-than-pleasure-the-secret-is-the-anticipation-of-a-reward/

Speaking on a personal level, I seem to get addicted to some things easily.  

When I was in college 40 years ago, I noticed something about playing table tennis.  After I hit the ball I had a high level of anticipation about what was going to happen next, which was only a couple of seconds away, but unknown until it actually happened.  I realized then that this high level of anticipation made the game addicting.  Pinball seems to work the same way.  

Maybe one reason why there is still a cult following for the 42-year-old video game Donkey Kong, which I still like to play, is that it has a great deal of randomness built into the game.  There is no set predictable pattern that you can follow.  Parts of the game are predictable, but frequently you have to react within a couple of seconds to an ever-changing circumstance.  The game can be an intense experience.

I think that there could be a similar appeal to gambling because the gambler is anticipating an unknown outcome.

On the surface, this would seem unrelated to watching a ton of youtube videos, which has been a problem for me lately.  Youtube has a bunch of interesting content, but even before you finish one video, they are recommending other content that you might like.  I have a natural tendency to be curious about everything, so I want to see what this other content has to offer.  There is anticipation there.  It is like they know how to keep me hooked.

TikTok has admitted that they use an algorithm to keep people addicted.  The way it works is that they show you a list of videos with the best videos interspersed along the list  The idea is to keep you scrolling looking for the best videos.  Maybe TikTok is evil.

Social media creates anticipation of positive feedback from other people.

Perhaps if a person is aware of how they are being manipulated on a psychological/neurotransmitter level, then maybe they can change their behavior by not falling for this trap.