To be honest, based on the title of this thread, I thought this was a rant about how annoying Harry Potter is, or question the logic behind the success. That being said, I'm just gonna voice my opinion, and hope that nobody takes it as an insult.
I personally never really got into it that much. I read some of the first book, but got too bored, so I gave it up. I only began reading it to find parts that were causing Christian parents to oppose having their kids reading the books as part of school assignments. I didn't get far enough into the book to find one, but then again, I didn't get far into it at all.
It just didn't appeal to me and, to be honest, I don't get why it's so popular. Maybe if I made it past the boring part I'd get it, but I'm one of those that needs the begining to tell me why I should care enough to go on, or to at least have something intriging enough to make me wonder about it's ending.