I know of three of 'em that are of walking distance from my apartment! It's midnight, you don't like cooking, but you've got a snack craving? There's a 7-11 somewhere nearby! They've even got things like contact lens saline solution (though they totally rip you off, but that's to be expected) and other essentials if you need 'em for emergencies. I'd hate to work there, but 7-11 is the best convenience store!