Well, we kinda talked about this a little before. And I would rather talk about something I love instead. But at the same time, I think I should still elaborate, for the protocol.
And we'll also include the anime that I hate in this question, because it's the same answer anyway and will save me the trouble of talking about it some other time.

It's still Aqua from Konosuba. Or Kazuma. Konosuba just sucks and its characters can burn for all I care.

I am an incredibly character focused viewer. I can forgive some plot holes, animation flaws etc., if I simply like the characters. And vice-versa, I absolutely can't enjoy an anime where I can't enjoy the characters. And Konosuba has some of the worst, most disgusting, atrocious characters I've seen in anime in 16 years that I've been watching it. Yes, it includes the protagonists of School Days and Mirai Nikki. I'd watch them over Kazuma and Aqua any day of the week. And I HATE those guys.

Konosuba's humor for me was annoying and to be quite honest, not funny at all. In no small part because it revolved around these horrible characters. There was one joke in the first season that I actually found funny and clever, the whole "hai, Kazuma desu..." gag. That's it. Everything else was just frustrating.

Darkness is the only main character that I pretty much have no problems with. She has an amusing and relatively harmless quirk that unfortunately got overused, just like all the jokes in this show. And with it being her only trait, because Konosuba's writing is bad and character development is non-existent, it's not enough to carry the rest of the show.

Megumi is kinda in the same boat. Although, I've heard that she gets really abusive with her friend later, which I can't confirm or deny, since I've only seen one season. But if it's true, I can't see how I can enjoy the character who keeps beating their friend out of jealousy. But again, that's hearsay, not my experience. Therefore I'm keeping Megumi on the neutral territory for good (since I'm likely never watching S2).

Meanwhile, Aqua is easily the most annoying anime character that I've seen. She is completely useless (and I'm not just saying that for meme's sake), spoiled, she whines constantly, bosses others around without contributing anything. Not to mention she's straight up dumb. Not an airhead. Dumb. I rated Konosuba extremely low when I first watched it, but even then, I tried to give it another chance, started the second season. I thought that maybe, just maybe, it gets better. But her constant hysterics made me drop it mid episode one. I just couldn't stand another second of her.

And then there is Kazuma. A selfish, cowardly prick with no interest in others' well-being who acts only for his own benefit. Always offended, resentful, ungrateful. That's not a protagonist you root for. He doesn't grow and he doesn't want to grow.
Compare him to Subaru from Re:Zero. Subaru is also a horrible person in many ways. Especially at the start of the novel. He's selfish, brash, angsty, has a huge social anxiety that he tries to hide in this "perfect world" he ends up in. He's really just an average asshole that needs to grow. But he grows. He makes mistakes, creates the cringiest of situations, but learns from them. He is a weakling, but learns to use others to compensate for his own inability. He's a hero that keeps evolving. Through humiliation, through pain, through death, through loss. He's broken and rebuilt from zero. To become a much better person. A true hero of his story.
Whereas Kazuma stays the same. He is stagnate, just like the rest of Konosuba's story. One of the worst written characters in anime history.

I can also add some minor things to this.
The animation in Konosuba is sub-par. It has great explosions and the boob physics in the succubus episode. The rest of it is just deformed faces, janky movement etc.
I don't like the story that has no stakes, not incentive for heroes to move on. Sure, it makes fun of an isekai genre, but you can do so while making a compelling story of your own, with characters that are easy to get behind even if they aren't the true heroes. Look no further than No Game No Life, which does pretty much the same, but better.

And it's not like I hate absurd humor in general. I enjoyed +Tic Nee-san for what it was worth. I had a ton of fun with Potemayo. And you already know how much I love Garupa Pico.
No. If you put likeable characters in ridiculous situations - it's fine. But if you put the badly written pieces of shit in those situations...

But these are, like I said, minor things that I may have overlooked if the characters weren't so sordid and detestable.

Alas, we have what we have. Aqua, Kazuma and Konosuba in general soak up most of my anime hatred.