Xenoblade Chronicles 2 would be the pinnacle of this for me. When I first played it, I couldn't understand the mechanics at all and dropped it almost immediately. I though about picking it back up again but it wasn't a priority
Fast forward a few months, I picked up the game again, and at first... not so different from before. It was okay, but nothing special. I kept going. Then, a few weeks later, I completed the game. I loved it. Something about it sticks with me today and I honestly consider this game to be a turning point in my life.
The aesthetics were stunning. The story... I dunno, somewhat above average. Combat? Actually pretty good, surprisingly, after I got used to it. I guess everything in this game just... worked, and I loved it. Nowadays it holds a special place in my heart and will not be so easily forgotten.
The original Hyrule Warriors on the Wii U turned out to be better than I expected, too. I don't believe I would be the only one who felt like this considering most of the people who bought it, like me, were expecting something more akin to Zelda. I actually ended up enjoying the hack-and-slash gameplay a lot and probably ended up enjoying it more than most main series games. Certainly ended up playing it a whole lot more, that's for sure.