It seems like every cartoon we ever watched needed a character whose sole purpose was to piss us off, and in the case of these 10, they were very, VERY good at it.
Tiny Toon Adventures - Elmyra Duff
I almost want to cut her some slack because she's a young girl who loves animals and clearly doesn't know any better, but good lord was she annoying for every second of her existence. Not only that, but hurting animals isn't exactly a great way to win any love from the audience.
The Flintstones - The Great Gazoo
You know your show's running out of ideas when you introduce an alien that can warp reality at will and that only one or two of the characters can see. Gazoo's antics were annoying enough, but his pompous voice just made him the worst.
Arthur - D.W. Read
D.W. was basically every bratty sister combined into one character. Tattle-tale? Check. Cries when called out on her BS? Check. Constantly snooping into things that don't concern her? Check. Ugh, she's awful.
Dexter's Laboratory - Dee Dee
It has to be hard to be a six-year-old kid with the mind of a genius, and it's gotta be even worse when your sister is a constant terror. Every time Dexter had a new invention or experiment in the works, you could bet that Didi would show up and ruin it.
Sure, she cared about her brother and was mostly just dumb, but it was hard not to want her to just go away.
The characters just get worse from here folks...
Caillou - Caillou
This bald-headed French Canadian abomination is the whiniest, most entitled brat to ever (dis)grace our TV screens, and even as a kid it was pretty much impossible to like him or how much he mouthed off to his parents.
Rugrats - Angelica Pickles
Unlike a lot of other characters on the list, you're kinda supposed to hate Angelica. She's mean (borderline psychotic even), she's spoiled, she speaks in perpetual screams, and above all else, she's obsessed with a crappy doll. Even when the kids all grow up, she's still the worst.
X-Men - Jubilee
Meant to be a surrogate for the "hip and young" crowd that Fox wanted to cater the show to, Jubilee just ended up being completely annoying. Between her terrible lingo, lame superpowers, and her constant need to be rescued, it's no wonder every other character was more popular.
Max and Ruby - Max and Ruby
Max is spoiled and Ruby's a bossy enabler. Nuff said.
Transformers - Starscream
Between his screechy voice and constant, CONSTANT attempts to try to usurp Megatron as the leader of the Decepticons, it's a miracle Megatron ever even bothered to keep him around, let alone make him second-in-command over much better characters like Soundwave and Barricade.
Scooby-Doo - Scrappy-Doo
The ultimate in unnecessary, annoying, and just plain hateable characters, Scrappy-Doo is easily one of the worst sidekicks in cartoon history. He was so bad they even made him a villain in the live-action Scooby-Doo movies!
Between his cocky attitude, perpetual getting himself and others into dangerous situations, and his lame-ass "puppy power" catchphrase, we really wish one of the show's monsters would just punt him back to the Stone Age... preferably with him landing on the Great Gazoo, killing both.