The basic plot is that Timmy Turner is a lonely, misunderstood ten-year-old boy who must deal with more than any boy his age should handle.... Ever. So out of sympathy, he is given Cosmo and Wanda, two bumbling fairies for personal servitude and company from Fairy World. But even with the two fairies at his side to help him 24/7, he quickly learns life is full of complications that even magic can't fix.
One of the reasons this show does so well is the large cast of characters. Everyone on the show gets a good laugh from me and that's what's important. Timmy's father, for example, is a clumsy, dense man and always undertaking some stupid task to get back at the... Dinklebergs.... Look up the word "evil" in the dictionary and you'll see a mug shot of Vicky, Timmy's babysitter, who cares only about money, the pain of a child, and... well, money.
Another reason of this show's success are the plots themselves. To get through life's challenges, Timmy uses his fairies' magic to the advantage. But, of course, nothing ever works out right. One reason is because of the rules added to the power of magic. After all, without restrictions on what Timmy could do, this show would be over in a snap. Also, each episode constantly throws in joke after joke after joke and, coupled with the quick animation and scene switching, it rarely slows down on its humor.
Now onto the heart of this wonderful show: the fairies. A regular comic pair. Wanda is sensible and smart, totally opposite of the purile idiot known as Cosmo. Their interactions with each other are often rib-cracking, especially since Cosmo is constantly getting on her nerves to no end. Adding to the fact that they are wed can ensure worse punishment for Cosmo in the end. They're always trying to work together as a team (a horribly dysfunctional one) and help Timmy, but you can always be sure Cosmo will add some "fun" along the way.
For real people, I can see nothing wrong with this show. Some of the reasons stated on here for its atrocity are total non-sense, such as the animation is bad or the characters all act dumb. Hello, it's a comedy. The characters act like that for a reason. As for the animation, there is worse, such as some of the things on Cartoon Network. (Dexter's Lab, PPG) It, and other shows like it, is actually a revival and tribute of an old style in the 30s and 40s that relied on an abstract look for uniqueness, so it had few details and the characters looked flat. And besides, so what if there's little detail and such? Is that really important in an animated comedy?
Alright, enough personal ranting for one day. Back to business. This show is absolutely wonderful. Good, quick humor, a huge and colorful cast of characters coupled with the premise of a boy with (nearly) infinite magical powers make this a must-see show for all. If you've barred this show from your schedule of "Must-Watches," at least give it a good chance. You may be extremely happy with the result.