I was older, so Harry Potter felt pretty thin to me when it came out. I had been reading Hitchhikers Guide to the Galaxy and Discworld stuff by then...

However, I have a similar feeling around the Grand Theft Auto games. When I was younger I just thought they were crass and funny. As I got older I saw them as a humorous and often accurate mirror of US society. The enjoyment, however, would wane when I realized how few people saw or understood the commentary but instead embraced the worst aspects of the games. It is harder to go back now and not see so much of it being horribly interpreted by the audience, even if I found the social critiques to be funny. It taints it a bit, but it doesn't mean I can't sometimes still just enjoy it for what it is.