Cosmo and Wanda (seasons 9 and 10)

Cosmo and Wanda are two of the six main characters in The Fairly Oddparents and are Timmy Turner's fairies. They've been flanderized since season 9 until the show's cancellation.

Bad Qualities

 * 1) They became flanderized
 * 2) *Cosmo was originally simply The Ditz and a bit of a Cloudcuckoolander, sometimes dim but still relatively normal, and perhaps strangest of all, he and Wanda seemed to be on an equal level of air-headed and careless intelligence. Now he's simply JUST the Ditz as opposed to being both that and an average cloudduckoolander
 * 3) *Wanda was also originally portrayed as being dimmer than Cosmo, believe it or not, then at some point, they shared an equal amount of intelligence. She became simply the wiser one who chastised Timmy and Cosmo whenever they did something wrong, but then all her jokes became nagging
 * 4) Speaking of nags, Wanda was one to the point where the Barbarian Hero episode had her become the whip cracking Nagules.
 * 5) They both seem to lose their wands a lot in these seasons, particularly in season 10 and depend on Timmy and Chloe to solve the problems on their own.

Good Qualities

 * 1) They are still there for Timmy when he needs them.
 * 2) The show wouldn't have been great without them.
 * 3) They still care about Timmy and their son Poof.