It's not just that Harry's world is so intricately woven and strewn with perfect details. It's more than pertinent politics, universal themes and modern morals. I think we love "Harry Potter" because Harry's universe is filled with the heavy, strong and close relationships that we genetically crave, but find it quite difficult to actually participate in these days. Those relationships appeal to children, of course (free from parents, undermining authority, earning the respect of their peers). But I don't think many people suspected how much adults long for these simple, unquestioned, "childish" relationships. There are no boarding schools for adults, nowhere for us to go and just be a part of something. Rowling's most powerful story isn't the battle of good vs. evil. It's the long and lovely explanation of Voldemort's weakness and Harry's strength: Friends, love, community. . . . that stuff we sneer at and call saccharine but that we need like a grindylow needs water.