man i might just be easily entertained but here's my rankings of the souls games by hours played:
ds2: 263 (ds2 regular 227, sotfs 36)
ds1: 213
ds3: 91
i played so much ds2. ive liked all three the same all for different reasons.
ds1 i liked because it was my first dark souls and it was a huge introduction into the series, and the world development was super memorable and beautiful, and each place had a different story to it and it all made sense in the canon.
ds2 i liked because it was so squeaky smooth 60 fps, it had different weapon animations, its multiplayer worked better, and there were less instances (than in ds1) where i'd die and blame the game, it was always my fault.
ds3 i liked because of how loving excited i was for it to come out, its world was much more convoluted and therefore felt more like it was created by natural/magic causes in the game rather than "a developer put this together" (a good example is the undead settlement, that stuff was really loving cool.) the enemies that were the most annoying were still like "i feel cool now that i killed that thing" rather than "forget that piece of stuff, glad i'm done with it." everything in that game was pretty satisfying.
overall, the biggest reason i liked the games was because it made me feel good at something. not that im bad at a lot of things, but i'm pretty decent at the PvE in that game (maybe not compared to other players but i dont die much now) so that was cool. that and i now know like everything about the lore and every character and it gave me a world to be engrossed in and imagine in my head, and not much in media makes me want to learn more about a universe except for dark souls.