I know that a lot of people play WoW and similar games and have no interest in story at all, too. Who's Arthas? Who cares! That's perfectly fine. Play the game how you enjoy it. While knowing the story of the world you play in helps, you don't really need it to enjoy many aspects of the game.
Out of pure curiosity, I've made a poll to see just how big the divide is between those types of people. Are you the kind of person that reads quest text, or do you look at the objective and move on? Do you know obscure details about characters that a lot of people wouldn't? Do you know why you go to the dungeons you do? A simple Yes or No poll is tucked behind the link below. Satisfy my curiosity!