>>50203081XY and ORAS. Utilities in this game are very well design and convenient for my playstyle. If I want to play comfy mini-games with my Pokemon to pass the time I can. If I want to EV Train I can do it whenever I want. If I want to do some light trading or even Random Battles with people I can hook up with them almost immediately. I have the Battle Chateau and 3v3 Battle Restaurants for casual battles against the CPU. Berry Field is a nice farming simulator with cozy music. Battle Maison is blessed for letting me take breaks between matches. There's just a ton of shit to these games that's very convenient and easy to replay.
XYORAS of course is also the last game to have a formal National Dex where I could collect all Pokemon from every game, check out their Pokedex entries and earn the diploma (I like how you can actually hang up your earnings on your secret base in ORAS). Looking back at my old collection almost feels sad now that the Dexcut is a thing. 3DS is the last stop.