The kid Cosmo and Wanda were going to be re-assigned to actually goes to the same school as Timmy, although he is only seen in background shots.
Timmy says it was only 6:04 in response to Vicky telling him to go to bed and Vicky says that it's 9:04 on the East Coast. This gives the viewers a hint that they live somewhere in the West Coast (which was eventually revealed to be in California in the episodes: Christmas Every Day and Fairy Idol).
This is the first time Timmy sees his Mom and Dad kiss.
This is also the first time we see his parents in full body.
Although this episode marks the first appearance of Chester and A.J., their names are not revealed until its sister episode "Power Mad".
Toy Story - The kid that the fairy messenger showed to Cosmo and Wanda is similar to Sid Phillips, due to his appearance and his toy abusing personality.
Big - Timmy wishing to become older is very similar to Josh Baskin wishing to become big.
Something breaking or dying whenever someone says Vicky's name.
The word "creep" or "creepy" being used to describe Timmy after he wishes to be an adult.
Characters injuring themselves while shaving.
Vicky blowing a whistle and attacking Timmy as an adult when she sees him.
When Timmy thinks about the deeds he will perform when he grows up, when he says that he will not tolerate bullies, Francis, A.J. and Chester look exactly the same to how they look in the present time, while Vicky bears a beard like if she was a middle aged man.
However, considering that this was just Timmy's imagination, he was most likely using them as metaphors of what he was going to do in the future.
It is unknown how the mean kid knew about fairy godparents. It may be possible that one of his friends, if he had any, lost his/her and told him about them. Furthermore, as he goes to Timmy's school, may be he heard stories about Mr. Crocker and his beliefs about fairy godparents.
After Timmy is transformed into an adult, Cosmo and Wanda's reaction was "Ewwww", but if you watch their mouths carefully, they seem to be saying something else.
It is unknown where Timmy got a car to drive as he's later shown to not have any money.
However, he later has two 5 bucks.
When Cosmo and Wanda say "...older Timmy", Wanda's top row of teeth keep disappearing and reappearing.
It's unknown how Timmy didn't forget that he had fairies after he became an adult as according to Channel Chasers and other future episodes, children forget about their fairies once they become adults.
It could be possible that this does not apply here since Timmy did not age himself with an actual aging device (the magic remotes aged people if they pressed the fast forward button). In fact, Timmy wished to being an adult to his fairy godparents, so in case it's a wish, that can't possibly count.
Also, considering how this was the first episode of the series, it's likely that this just wasn't canon at the time.
The adult Timmy from Channel Chasers looks different from the adult Timmy in this episode.
It might be because Timmy was much older in this episode than the adult version in Channel Chasers or that Timmy's wish altered the appearance he would have as an adult instead of the appearance he would acquire when the time arrive.
During the football scene, Timmy's hair that's outside of his helmet keeps diappearing and reappearing.
This episode implies that Fairy Conventions are a place where the fairies meet and discuss topics, though they're shown to be more like a Comic Con-like convention in Cosmo Con.
It is unknown why Cosmo and Wanda didn't go away after the other prisoners saw them.
It's possible that fairies are safe as the prisoners would likely not be believed if they said anything.
Mrs. Turner: Why soon you won't even need a babysitter.
Mr. Turner: Yep, but tonight you do. Hey, pronouns again.
(as Vicky rang the doorbell, a candle went out and a wolf howled)
Cosmo: Oh, no. the baby-sitter.
(lightning flashed in the background as the door opened)
Vicky: Hello Mr. and Mrs. Turner. It's me, Vicky.
(the flowers next to her screamed and withered)
Wanda: You can't spell Vicky without icky.
Mr. Turner: We'll be back really late, so tuck Timmy in, okay?
Vicky: I'll take care of the little darling like he was my own cash and blood. (Timmy's Mom and Dad drove away) Have fun at the movies! Bye! (her tone changed to her true self) All right, twerp! Time for bed.
Timmy: But it's only 6:04.
Vicky: Well, it's 9:04 on the east coast. BED!!!!!!!
(in Timmy's room, his clock changed from 6:04 to 6:05)
Cosmo: Now it's 9:05 on the east coast!
Wanda: Cheer up, Timmy. You're only going to be little for a little while!
Timmy: Well, being little stinks. I'd bet it would great to be an adult. When I'm big, I'm going to do what I want when I want, like helping little old ladies cross the street. I'm not going to take any crud from bullies, and I won't need a babysitter!
Timmy: Well, how do I look?
Both: (in an awkward tone) Eeeeeeeewww...
Timmy: 'Ew' is right! I don't have any hair!
Wanda: Sure you do! It's here on your back!
(Wanda lifted his shirt to show that his back was covered in hair)
Timmy: That's just creepy
Wanda: You know Timmy, When a kid helps an old lady cross the street, it's kinda cute
Cosmo: But when an adult does it, it's just plain creepy!
(Timmy, having wished himself to be older, saw his Mom and Dad kissing. He covered his eyes)
Timmy: Arrrgh! It burns!
Cosmo: I got an idea. Maybe if you eat some adult food, you have better luck thinking like an adult.
Wanda: Great idea, puddin'.
Cosmo: I'm chock full of 'em.
(Cosmo and Wanda laughs while the scene is changing)
The First Reassigning Fairy: Fairy-Gram for Cosmo and Wanda.
Cosmo: I'm Cosmo and Wanda!
The First Reassigning Fairy: Now that your kid is big and hairy, your next assignment is mean and scary.
Wanda: You mean we're being reassigned?
Fairy-Gram: Ha ha ha! I mean, yes, and we're all very sorry.
Cosmo: Can we have a couple of hours to say good-bye to Timmy?
The First Reassigning Fairy: Can I have five dollars? Two hours.
Cosmo: Miniature golf is a great kids' game!
(Cosmo and Wanda were turned into a tee and ball)
Timmy: Ow! My back!
Wanda: Let me try the Age-O-Meter. Kid...adult...Oh, no! You've become even more of an adult!
Cosmo: We've got to resort to the heavy artillery!
(cut to Timmy riding a kiddie ride outside a store)
Timmy: Can we hurry this along? I am running out of fives!
Timmy:(handing Francis a razor and shaving cream) Here!
Francis: Hey! Shaving would be fun!
(Francis walked away with the shaving cream and razor to try to shave his back, only to cut himself as he screamed in pain. Timmy and his godparents laughed at Francis' misfortune)
Timmy: I'm puny again, woohoo!
Cosmo and Wanda: And we get to stay with Timmy.
Wanda: In your face!
The First Reassigning Fairy: Well somebody gets assigned to that mean little...Da...Darn it.
(The First Reassigning Fairy poofed away, becoming the fairy godparent of the mean kid)
Mean Kid: Finally. Did your head pop off?
The First Reassigning Fairy: It's not supposed to.
Vicky: I'M SAFE, I mean... you're safe, which means I'M SAFE!!!!
Policemen: You are one creepy adult. We've got a place for people like you.