1: The characterization of Luthor as the insane, solely petty jealousy driven mad scientist. I personally prefer the machiavellian business tycoon/legitimately respected scientist who has many noble intentions but very ignoble means and a pathological distrust of superhumans and aliens, mainly because that's the Luthor I grew up with and I'm rather drawn to the idea that the biggest villain in the DCU is a man who truly wants to do right by the world, but his own shortcomings and flaws twist and corrupt that desire to do good into something nasty.