Can someone tell me exactly what is so fun about minecraft?
I think that sums it up. If you have a particular personality type, it's a very compelling game. If you love twitchy FPS games you'll probably hate it. If you like games where you think "I wish I had windows, I should be able to make glass out of all this sand" Then you try putting sand in a furnace...and it makes glass, you'll probably enjoy it. Nexa and I generally play games together as we have a small amount of time that we can dedicate to some sort of leisure activity that doesn't involve the children (although Hannah plays minecraft, it's an amazing game for kids). We, Nexa especially, tend to overthink modern games. "Maybe we have to cut down a tree and make charcoal to get the guy to give us the drawing?" No, we just follow the arrow to him and click on the box. In minecraft, most of the things just actually work the way we'd expect. You do cut down a tree and make charcoal if you can't find coal to burn. If you pour water on lava it makes obsidian. If you dig clay up and fire it in a furnace it makes brick.
You get the idea. I assumed a lot of things about the game before we played it. I was wrong about most of them. It's easily one of the best games I've played in a decade. Replay value is absurdly high, along the lines of Total War or Civ games, if you're that kind of gamer. I recognize that's a high standard, but it meets it for me.