Bendy (Foster's Home for Imaginary Friends)

Bendy is a one-time character from Foster's Home for Imaginary Friends, who appears in the infamous episode, "Everyone Knows It's Bendy" as the titular main antagonist. He is the imaginary friend of a boy named Gregory who was sent to Foster's because of his troublemaking.

Why Everyone Intentionally Knows He Sucks

 * 1) For obvious starters, he caused trouble all over Foster's. He is characterized as a troublemaker who enjoys putting everybody through awfulness and always succeeds at doing so.
 * 2) His characterization is really flat and one-dimensional. He gets Bloo, Coco, Wilt, and Eduardo in trouble for no explainable reason, although this is likely because of the episode’s bad writing.
 * 3) What makes him especially infuriating is that much like Sarah (from Ed, Edd n Eddy), Rodrick Heffley (from the Diary of a Wimpy Kid book series) and Micah Brill (from the Goosebumps book "Revenge R Us"), he has no good reason as why he acts this way or why he got Bloo and his friends in trouble other than because he can.
 * 4) * Though to be fair, this is also the result of bad writing in the episode he appears in, and the fact that a lot of important scenes were cut from said episode, presumably due to time constraints doesn't help in the slightest.
 * 5) He is also an incredibly pathetic antagonist as well, since the very fact that he always fake-cries to both Frankie and Mr. Herriman every time he intentionally causes trouble which makes him come off as nothing more than a spoiled brat to the point that you will most likely not take him seriously.
 * 6) He fooled Frankie and Mr. Herriman and convinced them to take his side over Bloo, Coco, Wilt & Eduardo with his made-up sob stories, making them both additionally out-of-character as the two know for a fact that the other imaginary friends had lived at Foster’s longer than Bendy has.
 * 7) * Worse still, his acting skills of making up sob stories are very poor and unconvincing, so much to the point that each time Frankie and Mr. Herriman fall for it, it makes the two look like complete idiots.
 * 8) Whenever he is about to cause a misdeed, or most infamously, gets anyone in trouble and gets off scot-free after that, he makes an evil grin which is extremely punchable.
 * 9) Near the middle of the episode, Bendy acts very mean-spirited to Bloo; the worst example is during the intercom were after poor Bloo gets banned from doing his favorite things until further notice, Bendy then uses Bloo's toothbrush to clean the toilets, which is utterly mean, not to mention outright disgusting.
 * 10) His voice by Jeff Bennet is very irritating, whiny, and ear-piercing, such as in the annoying scene where he and Bloo tried making a louder laugh at each other, in addition to whenever he fake-cries in front of both Frankie and Mr. Herriman.
 * 11) He never gets any comeuppance for framing the others out of malice and gets off scot-free at the end, making him a high-profile example of a karma houdini.
 * 12) While his design is pretty creative by the show's standards, it looks like a rejected design for the Grinch.

Redeeming Qualities

 * 1) He did get initially scolded and blamed for flooding the house at the end of the episode, which is perfect karma until Bloo ruined it by explaining his revenge plan.
 * 2) Since he is the main antagonist of the episode he was pretty much meant to be hated.
 * 3) He thankfully gets his comeuppance for his actions in the videogame Foster's Home for Imaginary Friends: Imagination Invaders, by getting scolded.

Trivia

 * He is the first character in Foster's Home for Imaginary Friends to be written out of the show, and is classified as a 100% non-canon character. The second and third characters are Goofball McGee and Jamze Withazee in that order.
 * Despite not appearing in any other episode of the show, Bendy's signature was seen on Mac's 'Goodbye' card in the series finale of the show, "Goodbye to Bloo", though it might be another character who's also named Bendy.
 * Despite him appearing in one episode, he has been featured in other Foster's Home media outside the show. In the Game Boy Advance game, he appears as an enemy who throws items at the player. In the Leapster game, he steals Cheese's horse and causes Bloo to go on a quest to stop him. In the Nintendo DS game, Imagination Invaders, he breaks some busts and draws on a wall, but then, Bendy gets caught by Bloo.
 * Both Craig McCracken and Lauren Faust, who wrote the episode "Everyone Knows It's Bendy", admitted to have regretted creating Bendy, owing to the negative reception the character and his debut episode had, so much to the point that Bendy in general is completely ignored from the entire show in subsequent episodes.