These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Desert Punk
Darkness-Induced Audience Apathy: Almost every single character is a massive jerkass, and the few exceptions never prosper in this world. By the middle of the series, it's quite clear that none of the three major characters have a Hidden Heart of Gold. Pretty much summing things up is the comment by the Lemony Narrator in the last episode in respect to the After the End setting, which is to the effect that "With people like this, it doesn't matter if humanity goes extinct."
Harsher in Hindsight: Remember all those "endearing" traits Kanta had that were Played for Laughs? After the reveal of his true nature, go back and watch the series again and you realize it's not quite as funny anymore.
Love to Hate: Kanta, the main character himself. He's an unrepentant asshole who only looks out for himself. Many fans would also argue that he is a hilarious character because of how much of a selfish Jerk Ass he is.