Shopping at Costco is something like a hero’s quest with multiple narrative conflicts: man against man, man against society and, most importantly, man against self. In every direction, Costco leads you into temptation – vats of sugar and fat, tubs of chemical dipping goop, sensible slacks that share a brand name with the giant jar of minced garlic – and everything is priced to deliver you straight to the doorstep of your evil consumerist impulses.