I would love to be able to say Far Cry 3 as well but by the time I unlocked the second island (which I deliberately left some bases uncaptured), did the ammo/carry hunts and finished up with the story then I was done, indeed it might be a bit cliche to say post Vaas and I would say it held on for a few more hours for me than that but not many. If I could have reset the island a bit, or had to make some harder decisions with perks I might but I was mostly done, which is not something that happened with GTA other than the first part of 3 (the mafia with shotguns there meaning you pretty much had to rock up in a tank as anything else would not survive).
It is not that I did not have a great time with the game (indeed regret waiting for as long as I did to play it - think 5 was out by then) but as a candidate for never get bored then nah.
Give me a decent version of tetris and despite playing it for possibly tens of thousands of hours (I used to use it as a keep my hands busy game while watching things) I will continue to enjoy it. I don't know that I can still properly go for the original gameboy version or DX version there, though NES version of 2 still works for me, and instead I will go for either tetris grand masters (has a nice homebrew version on the DS) or Tetris DS. Either way though arranging those falling blocks... still does for me.
If I am not allowed that.
MX vs ATV on the original xbox. Nothing has ever quite come close to the zen feeling I get playing that in free roam with a friend on the same TV just messing around, making our own fun or similar. There are sequels but they tended to shrink the map, and post buyout they went down a different path (almost more simulation than silliness of the xbox version). I am told later versions of Monster Energy American Motorcyclist Association Supercross Fédération Internationale de Motocyclisme World Championship The Official Videogame ( https://gbatemp.net/review/monster-energy-supercross.747/ for my review) got more of a free roam in sequels (I kind of did something there in the track creator) but I have yet to do those.
EA's Skate 2 and Skate 3 also seem to still work for me. Free roam, having my own fun. Yeah, maybe not quite to MX vs ATV levels of zen but just about moving in the same circles.
Also might want to say Elite (not played the new one so originals/the new kind) for similar reasons.