Update from original: I got rid of Cecil Terwilliger from The Simpsons, Tweety Bird from Looney Tunes and Sweetie Bird from Tiny Toon Adventures, Stan Smith from American Dad, Peter Griffin from Family Guy, Glen Quagmire from Family Guy, and Nermal from The Garfield Show because they had enough hate. And sorry .
The entire cast of Teen Titans Go: Good heavens Titans, what did CN do to you? I can't even describe how flanderized they were in this incarnation: Robin's a douche, Starfire's more of a ditz, Cyborg and Beast Boy are total idiots, and Raven... A pegasister, really?
Bloo from FHFIF: Speaking of flanderization, this poor guy got it the worst after the pilot movie of Foster's; House of Bloo's (IDK why it's called that) Bloo went from nice, a little misguided guy into a total and complete jerk after the pilot movie, which was good. There was nothing redeemable about this "character development", the only time I felt bad for him was in the episode, "Crime after Crime" (one of my HATED episodes) when he's trying to get punished and not eat supper which is "It" (vomit; actual vomit) when he's trying to help Mac from the cops, Eduardo slammed the door on him, Bloo was explaining to Eduardo why he's lucky not to go to supper, for some extremely stupid reason, he sent Bloo to supper, which he was trying to avoid! And Bloo has to eat more during the credits... I'm surprised that Bloo did not get revenge against Eduardo for sending him to supper.
Mama Robotnik from AOSTH: She's the worst mother; she took Dr. Robotnik's teddy bear (while he was an infant) in hopes of turning him evil (which works). MOM from Futurama was a better mother than Mama Robotnik...
Percy Femur from Doug: He's way worse than Roger!
Bendy from FHFIF: I hated "Everyone knows it's Bendy" (along with "Crime after Crime" and "Frankie my Dear"). If anything, Bendy should've been the jerkass of Foster's instead of Bloo.
Colin from Animaniacs: This kid, his 'sketches', and his stories aren't funny! Seriously, this kid makes both the Hippos and Chicken Boo look as funny as Bugs Bunny. Overall, he's more boring than the Hippos and Chicken Boo (who seem more funnier than Colin by comparison) combined. But I'll admit that he and Skippy Squirrel make pretty good friends.
Drusilla and Minerva from The Garfield Show: These 2 have poor fashion sense with dressing others
, and obsessed with making pets like Garfield look like girls, get a life you two!
Katie Ka-Boom from Animaniacs: She's hands-down the worst Animaniacs character!
Worse than Ms. Flamiel, Plotz, Colin, Mindy's parents, and Pesto combined! She gives teenagers a bad name, she makes the Hulk himself look like he took anger-management classes! I'd like to see the Saddle-Rager (AKA Fluttershy) kick her flank.
Spoiled Brat characters like Montana Max from Tiny Toons, Princess Morbucks from PPG, Whittany and Brittany Biskit from LPS, and Diamond Tiara from MLP:FiM: Nuff said. I'll admit that Whittany had a chance to being friends with Blythe in "Door Jammed"(too bad it did not last very long...), where as Brittany did not. I find Angelica Pickles to be more likable compared to any of these characters.
Elmyra Duff from Tiny Toon Adventures:
described her best in her version of this meme. She does not deserve to be in all WB cartoons in the 90's, and she does not deserve her own show.
Dishonorable mentions:Cecil Terwilliger from The Simpsons
Tweety Bird from Looney Tunes
Sweetie Bird from Tiny Toon Adventures
Stan Smith from American Dad
Peter Griffin from Family Guy
Glen Quagmire from Family Guy
Berry and Cheese from FHFIF
Herbert from Family Guy
Tricia from 6teen