What's the game you play when nothing else sounds good?
Do you have a game you play over and over, when nothing else fits your mood? That game that is infinitely re-playable, somewhat the same every time and somewhat new and interesting?
For me it's the games in the Orcs Must Die series. But mostly OMD 3. I play the mode called Scramble, where you have to beat 5 rounds of orcs, and they get harder and harder as you progress. There are random things to make it harder (nerfs) and you can choose 1 thing per round to make it easier (buffs). I've probably played that something like 300 times now since I beat the main game + DLCs a long while ago. I go into a special mental state while playing, since I know it all so well, and just zone out for about an hour each time.
Patient gamers, what's your "I will keep playing this game for the rest of my life" fallback?
I did that a lot with Subnautica but I think I've worn it out. I would make up challenge runs for myself to spice it up and I've run out of those. It was my "I want to play a video game right now" game. I kinda wish I had fewer objections to Subnautica 2, because there's things I like about that game and things I don't and the don'ts slightly outweigh the things that do.
It's great, go play it, and I suggest going in as blind as you can.
I once saw a playthrough by Let's Play Easy Mode, I don't know how he acquired a copy of the game while knowing as little as he did about it. He correctly guessed there'd be swimming in it and realized about six minutes in that it was a survival game.
I like to give this one hint, which I think is enough guidance to keep you from looking up the wiki and encountering actual spoilers: The answer to "well, now what?" is "go deeper."