YMMV / Make a Wish

  • Hilarious in Hindsight: the shopkeeper tells Harry that the reason Dumbledore can't defeat Voldemort is that he was so horrified of himself after killing Grindlewald that he chose not to kill another human being ever. Canon would later reveal that Grindlewald was actually alive.
http://tvtropes.org/pmwiki/pmwiki.php/YMMV/MakeAWish