One of my favorite Minecraft Mods was equivalent exchange. It foretold the coming of modern idle games. You work hard in the beginning to earn your first magical item, that gives you some sorcery that lets you spend less time gathering resources.

A small amount of time later, you get another magical item that lets you transmute a little more efficiently. A few dozen grinding hours later and you've acquired an array of items that grant you limited control over the environment, and you start grinding towards your first resource generator, which gives you resources which let you make the second one.

Now you're scaling. Build speed becomes the bottleneck for awhile, you're grinding the farm. Eventually you reach the next tier of generators, and this unlocks new mechanics. Finally at the end of the game you get artifacts of immense, game-breaking power.

Once I started playing, I couldn't stop until I had done all the things. And when I was done with that, I never picked it, or Minecraft, back up again.

The lure of mastery is perhaps the most addictive one that could ever be dreamed.