The Wind Waker for me. At the time, the open world and sea felt so massive, and the colorful cell-shaded graphics made me feel like I was immersed in a cartoon. I played other Zelda games before, but it was the first one to hold my attention all the way to the end. To me, it’s one of those games I wish I could experience again for the first time.
Windwaker would've been an easy #1 for me if it weren't so stretched out. The ocean really didn't need to be that big, I remember many times where I was just holding forward on the boat and browsing my phone for 5 minutes.
What got me was the Triforce hunt. Nearly no guidance/signposting, constant trips back to tingle, then back to a warp point, then sail around, rinse repeat. Ugh.