RDR 2 is just really the king of this, I am absolutely amazed at the amount of care and detail rockstar placed into everything. There's the obvious stuff like newspaper articles, store catalogues, horse behaviour, Arthur's appearance changing. But they really are just scratching the surface. The amount of unique animations for things that you would really not expect a game to animate, landscape slowly changing over the course of the game as stuff gets built, all the crazy animal behaviours -- I mean jesus, I saw a cat randomly scratch a wooden post to sharpen their claws or saw a dog try and play with my horse as I was buying something in the store. But visual attention to detail isn't really something that truly makes the game better IMO. It's all about the small interactive moments that occur outside of the usual gameplay circles. Like, RDR 2 is a shooting game, but there is more to it than just that.
For example there's the camp which probably has more unique, non cutscene interaction in them than most games do throughout their entire lenght. Sitting down to play cards with your gang members feels so good in RDR 2 - because it's actually fully animated, with hundreds of banter lines and the life doesn't stop just because you sat down to play, stuff still happens in the background, you can hear and see it all. I loved how you had an interact button for every npc, how your actions were constantly judged by people around, how you could perform completely pointless chores just for the hell of it. All of this just made the world feel much more genuine and lived in. I wished so many times playing The Witcher 3 that I could just sit down at an inn to have a drink instead of my inventory menu popping up whenever I bought something. Or that there were more minigames besides gwent - that one quest in Kaer Morhen where you get drunk was amazing, and I really wanted just to have more interactions with my fellow witchers or all the people that I met during my travels, but... there is nothing. There aren't really random npc events or unique npc interactions outside of quests.