I always go back and forth between Wind Waker and Majora's Mask as my favorite Zelda games. That's not just because they are both great: but they are tonally complementary games.
Where Majora is bizarre and somber—about averting an apocalypse—Wind Waker is happy and upbeat. It takes place in a cheerful post-apocalypse! It's in this mood: this love of exploration, this expressive character, that makes it so memorable.
The game is a classic 3D Zelda, but on the high seas. You must pilot your tiny boat—The King of Red Lions—across the oceans of Hyrule, finding islands full of treasure, danger, and intrigue. There are dungeons and towns—some of the finest in the series. But there are also plenty of tiny islands that just have puzzles or little secrets on them, dozens of reasons to keep sailing and seeking everything this world has to offer.
The world itself is incredible. I'll never forget the gloomy beauty of the Great Deku's pond and the Forbidden Forest Dungeon, the creepiness of the Earth temple, the vertical puzzles that made the Wind temple so much fun to figure out. Sure, there are fewer dungeons here than in most 3D Zeldas, but they are better integrated into the land—and sea—of Hyrule here.
And the combat! The combat is possibly the very best the series has had, next to—maybe—the recent Breath of the Wild. There's a musicality to it, a rhythm. And besting harder foes—like armor wearing bokoblins—requires some strategy. Should you knock off a helmet or breastplate first? Go in charging or hang back and counter-attack?
Finally, it's a game of expressive, cheerful character. Link and Tetra make the very best faces. Everyone, from the townsfolk on the islands to the monsters crawling the dungeons moves with personality and even bounce that is hard not to fall in love with.
That carries to the entire game. If there's one word I'd use to describe Wind Waker, it's joyful. That's an incredible thing to pull off, especially in a post-apocalypse.