I hate it when we go deep into a character's psyche or add more background to him. I just want to see them be funny, not make us feel sorry for them. Retcons go this way, too. For example.
Ed, Edd n Eddy's Big Picture Show- We learn that Eddy is such a jerk is so he can impress his older brother, who turns out to be an even bigger jerk. It's funnier to just have the Eds make scams and try to fit in rather than go into a deep, horrid personality.
Courage the Cowardly Dog- "Rememberance of Courage Past" shows how he got abandoned, which is very heartbreaking. What makes up for it is the happy ending of how he got adopted by Muriel. Also flashback scenes from "Curse of Shirley" and "Farmer Hunter, Farmer Hunted".
CatDog- Though I do like the special, "The Great Parent Mystery" can do this for some, as we like it when Cat and Dog try and scheme their way to the top.
King of the Hill- "A Rover Runs Through It" retcons Peggy's mother from basically an older Peggy into a total jerk (with a new appearance to match). It also establishes that the two haven't seen or spoken to each other in years, despite her meeting in episodes prior.
SpongeBob SquarePants- Some flashbacks, like in "Sing A Song Of Patrick" and "Blackjack".
Scooby-Doo: Mystery Incorporated- In the season finale, we learn that Fred's life has possibly been a lie and several fates have befallen the gang, leading to a possible split-up for Mystery Inc. Plus we see the characters with their parents and in high school, instead of just showing them going to one interchangable mystery after another. Also compare Fred's dad from "Mystery Inc." to "Scooby-Doo: Pirates Ahoy" and notice Scooby speaking in full sentences.
Ed, Edd n Eddy's Big Picture Show- We learn that Eddy is such a jerk is so he can impress his older brother, who turns out to be an even bigger jerk. It's funnier to just have the Eds make scams and try to fit in rather than go into a deep, horrid personality.
Courage the Cowardly Dog- "Rememberance of Courage Past" shows how he got abandoned, which is very heartbreaking. What makes up for it is the happy ending of how he got adopted by Muriel. Also flashback scenes from "Curse of Shirley" and "Farmer Hunter, Farmer Hunted".
CatDog- Though I do like the special, "The Great Parent Mystery" can do this for some, as we like it when Cat and Dog try and scheme their way to the top.
King of the Hill- "A Rover Runs Through It" retcons Peggy's mother from basically an older Peggy into a total jerk (with a new appearance to match). It also establishes that the two haven't seen or spoken to each other in years, despite her meeting in episodes prior.
SpongeBob SquarePants- Some flashbacks, like in "Sing A Song Of Patrick" and "Blackjack".