Even if a game has loads of side content or a meaty post-game, my urge to keep playing a game usually completely ends once the credits roll. There are exceptions, especially with Bethesda games and Pokemon.
Similarly, I'm usually not into gamemodes that don't have some sort of endgame. I like having an established goal.
I've never played the expansion packs for Skyrim, my favorite game, or The Witcher 3, another one of my favorite games. I swear I'm gonna. Honest.
I really like The Surge, and Code Vein was pretty cool, but I still haven't played a From Software game. I was really turned off by the inability to pause, but it didn't end up being a problem in Code Vein, so I'm more willing to start the Souls games now. I've seen some Souls deaths that look really bullshit and unavoidable though, and I'm looking to get challenged, but not frustrated.
I really like crime sandboxes like Sleeping Dogs, Watch_Dogs, and Saints Row, but I'm not that into GTA.
I hate the writing in the Yakuza series. Unbearable. I know cringing is a very trendy and overused reaction online, but truly, Yakuza's storytelling makes me cringe.