I can't decide between Super Mario Odyssey and Breath of the Wild.
On the one hand, Super Mario Odyssey made me feel like a kid again, and I can't really get that feeling much any more (outside of Kirby games).
On the other hand, I still go back to Breath of the Wild every once in a while, about 10 months since I got it. I just finished up the Champion's Ballad quest, and the reward is something I need to take around Hyrule.
So yeah, I've got a tie... though if I had to pick just one, I'd probably pick Odyssey, just because I really love platformers.
Other games I liked last year that I couldn't put up with those two include Cuphead (it was a fun time, hate that doctor tho), Hollow Knight (which I still have yet to beat... stupid beetle soldiers), and A Hat In Time (which I primarily bought because nostalgia, but it was much better than I expected, I could easily put it behind BotW and Odyssey as my 3rd-favorite game of the year, and it has mods too... I really gotta go back and play more of this one).