OK, I've got a better one now and I'm really surprised nobody has mentioned it. Who here remembers Catdog? It was a Nicktoon around the time of Hey Arnold and it died out around the time Spongebob began his meteoric rise (if I remember correctly). Catdog is currently being aired on Nick's overnight 90's block.
Anyway! What's my issue with Catdog? The premise of the show seems to be to focus everybody's hate and aggression on one pair of characters: the titular Catdog. Catdog are a pair of conjoined brothers, one cat one dog and they're attached at the waist like this:
So the first obvious question comes from how they eat and dispose of bodily waste but luckily I don't recall that ever being an episode. As you might be able to tell from the above, Cat is the smart one and Dog is the dumb one and in a way, these characters can be summarized as Proto-Squidward (Cat is a stuffy, snooty, Snoot) and Proto-Spongebob (Dog is a manic, hyper-active idiot). You may recall Squidward's line, "Why is it that whenever I'm having fun, it's wrong?" This line basically personifies Cat's character since many plots involve ways for Cat to go off and do his own thing so long as he cuts Dog out of his life. This also manifests in episodes where something catches Dog's attention and, as Dog runs off to chase a plot, Cat is literally dragged along. When the plots aren't doing this, the show has a gang of bullies (the Greaser Dogs I think) who routinely beat up Catdog (they tend to focus on Cat more often but Dog is never fully ignored by them and their beatings). When Catdog aren't being terrorized by Greaser Dogs, they're bothered by their rat room-mate Winslow who is a chronic asshole. The other recurring character who seems to be in every episode is Rancid Rabbit who functions in exactly the same way as The Red Guy from Cow and Chicken but unlike The Red Guy, Rancid Rabbit is another straight-up asshole character. Red Guy seemed to be made of self-parody in a way and while he too was an asshole it was incredibly difficult to take him as a serious threat. Rancid Rabbit on the other hand seems to live to make Catdog's lives miserable and take all of their money to boot.
The absolute worst part of the show is how often Dog seems to be the overall target of all of this abuse the show hurls at the titular characters. Sometimes it's indirect: as the dumb character it's easy to believe that Dog can't foresee issues that would arise from his own shenanigans. Other times it seems much more malicious since there are a number of episodes that rely on Cat doing something that would either alienate or else screw over Dog in a way that Dog is able to understand. These generally end in Cat listening to his conscience and cutting out the dickitry but we still have to sit through a sad-dog scene.
I feel like I've seen a lot of elements in Catdog in other cartoons; Cow and Chicken, Rocko's Modern Life, Ren & Stimpy, Spongebob...and when all of those shows have Catdog-like elements, they're generally done much better. Catdog is such an awful, mean-spirited show that it's ruined Jim Cummings for me. The legendary voice actor who's likely given your favorite childhood characters their voices (Pete from Mickey Mouse canon, Whinny the Pooh and Tigger too, Ultra Lord, Fuzzy Lumpkins, even Dr. Robotnik in 93-94) is somebody who I absolutely can't stand listening too simply because he voiced my most hated animated character from my childhood.