Fairly Odd parents is actually in the habit of breaking the crazy specifically inhibiting rules established in other episodes on a frequent basis.
For example Fairly Odd Parents often doesn't seperate whether Fairies ability to transform is an inherant ability or a product of their magic assisted by a inherant ability. The rule where the Fairies cannot maim people is broken all the time. Whether or not the rules are enforced by the rule book or by Jorgan changes. How magic even works changes all the time (It seems to be electricty but the Anti-fairies shouldn't have a source of magical power).
Characterisation is everywhere.
However there is one HUGE HUGE plothole in Fairly Odd Parents that was never resolved that was brought up from a movie. In fact it is so huge and mind boggling that it makes no sense and actually kinda kills the movie for me all on its own.
In Wishology, all the starts (or most of them at least) were told to be Buff Super Fairies similar to Jorgan. He defeats the Darkness (Three times) with the third being for good and yet none of these fairies EVER come home. This REALLY bugged me and I like this show
The one episode I hated the most in Fairly Odd Parents was when Crocker was cured of his fairy hunting ways for good. It ended with
Because Crocker was required to power all of fairy world they forced Crocker to believe in fairies and his therapist. Thus ruining both their lives. Honestly it is just so outragously malicious that I couldn't enjoy it. He was getting on with his life and the show demonstrated time and time again that Crocker is in fact a very intelligent and hard working individual when you seperate him from his Fairy Obsession. The fact that they are forcing him to go back to a ruined life where he is continuously unhappy is outright vicious. It would be the second time Timmy Turner ruined his life, except this time it was intentional.
As for my favorite episode... I have to admit I am a sucker for every episode that involves Momma Cosmo. They tend to be both funny, I love her brand of evil, and sweet at the same time. I really dislike it when Cosmo shows disinterest in being married to Wanda when these episodes are always there to show how much Cosmo truely loves her to the point where he doesn't even notice other women. I like the show when it has a lot of heart and is funny at the same time.