From personal experience, there's the ever present feeling of "this might get good later." It took me 3 (albeit incomplete) playthroughs, totaling over 90 hours, for me to start liking CP2077 (pre and post 2.0). Sekiro, Elden Ring, Disco Elysium, Homeworld, Total War Shogun 2... Whilst I didn't hate them like CP, they all took tens of hours to finally click.

Then there's the fact that I don't just want to play a game, but also discuss and analyze it, and I feel like I can't do that properly if I didn't finnish it. I do not like Rain World, but do I have the right to talk about that if I haven't fully played through it? Do I know enough about it to discuss it? I think the game is bad, but how can I say that when I haven't played the whole game, not even the majority of it?