BHWW I laugh, partly because of all of the creepy, obsessive adult fans of YA books out there and partly because for some folks in online genre-lit circles it's become this weird badge of honor for them to loudly proclaim "LOOK AT ME, I READ BOOKS FOR TEENS" and sing the gospel of how totally awesome books aimed at teens and kids are compared to adult-lit.
pastorofmuppets I wouldn't call Langdon a Mary-Sue, because that implies he's a semi-fleshed-out character instead of a bag that causes and effects are pulled out of.