It wasn't just a game you could play endlessly, but a game you took part in its creation.
The quests were fun to complete, but they were secondary to everything the game allowed you to experience. I got more fulfillment from looking at scenery and sneaking into places I shouldn't be, then combat. But I must say, it's quite a blast to duel-wield a couple war axes.
Skyrim did what it set out to do despite its foibles and glitches, which for the most part were hilarious rather than game breaking. I can still remember my first time getting smashing 300 feet into the air by a giant. What a magical experience!