- CatDog: The Great Parent Mystery is full of these, but this one reveals Cat's true character beyond the shadow of a doubt. After their long journey and Dog begins expressing doubt over ever finding their parents, Cat reassures him by telling him that they will always have each other. "We are brothers."
CatDog, CatDog alone no more is the little CatDog.
- The ending's reprise of the theme song
Giant Monster: HI HO DIGGETY!
- The giant blue monster's benevolent Wham Line:
Dad: (paraphrased) Well, we don't know where your mother came from either, but we don't care because she's your mom and you're our boys.
- CatDog's dad explaining why none of them question who CatDog's biological parents were.
Mom: (gasps and pulls out the half of the binky that was left behind after CatDog was separated from them) You kept it!
- The moment when Cat pulls out his half of the binky he and Dog had as babies.
- When it seems like CatDog and their adoptive parents are screwed by Winslow, The Greasers, and a slew of other individuals for the sake of Jerkassitude, the Tornado that separated the two from their adoptive parents comes in, and by sheer luck, it throws the formers away to Nearburg and the latters get eaten by the lake monster. Considering everything CatDog go through, it is satisifying seeing all the asses who give them hell finally get Laser-Guided Karma and CatDog finally get the happy ending they derserve.
- The montage at the end of CatDog and their adoptive parents spending time together and doing things like going to the beach and decorating a Christmas tree. It's just so touching to see them be a family again.
- Really, any time Cat sticks up for his brother is this, showing that he still cares for Dog despite all the stuff he does to him. For example, in "CatDog 3001," Cat and Dog have been separated from each other because the people of the future think Dog was a hero and want him to save them from a giant descendant of Winslow. Winslow's descendant defeats Dog, but Cat sees what happened to his brother and - in what is also an Awesome Moment - puts him and Dog back together and beats the bad guy by using Dog as a vacuum to suck him into their body.
- Winslow falling in love with a Con Artist rat girl in "Winslow Falls in Love". Quickly turns into a Tear Jerker when she steals his stuff and leaves him.
- Near the end of "Talking Turkey", Walt successfully travels to Turkeyburg, where he finds his mother and happily reunites with her, since he originally thought that she never made it to Turkeyburg.
- A minor one at the end of "Flea or Die"; the fleas end up so out of control that even the fleabelt can't stop them. This leads Cat to realize that their only chance is the flea bath Rancid had offered them earlier. When they get to the hospital Rancid is visibly horrified at how out of control the fleas have gotten and gives them the flea bath with no (apparent) ulterior motive. Hey, coming from Rancid, that kind of thing is huge.
- This lyric from the full version of the theme song:
A lunatic dog and a frustrated cat
Opposites this, opposites that
Internal struggle for two-in-one brothers
Scratching and biting and loving each other
- "Cat-Diggety-Dog" in its entirety.
- Anytime the Greasers act as each others' True Companions. As horrible as they are, it's sweet that they stick together.
- From "Vexed of Kin", Cat Dog's parents assuring Cat that they love both of them equally after he spent the whole episode feeling like The Unfavourite.
- Dog telling Cat that he is his favorite brother.
- Anytime there's a flashback to Cat and Dog as babies. Cute Kitten meets Precious Puppy.
- Their appearance in Ballad of Old 159 is especially precious. They’re shown curled up sleeping in their crib, and dog has his arms wrapped around Cat◊.
- In "A Very CatDog Christmas", Cat calls his usually unwanted guests (the Greasers, Eddie the Squirrel, Winslow, Rancid Rabbit, and Rancie) like family. They all have a group hug for once, not hating each other like in every other episode.
- The entire Brother's Day episode is just chock full of sweet moments: Dog being moved to tears by the brothers' day commercial, Cat talking with his loofa and Dog showering Cat with affectionate licks after Cat gives him his present are some highlights from the episode.
- Randolph cheering Dog up in "Catdog's End" by making armpit noises and going clubbing with him. Although it could be seen as Ho Yay, it's sweet to see a rich celebrity bond with Dog, of all characters.
- Lola and CatDog apologizing to each other and becoming friends at the end of "Sweet and Lola".
- In a way, the ending of Picture This. Dog is ashamed to find everyone in Nearburg angry about the pictures he took of them, but when his work is praised by an art critic, everyone forgives Dog and they encourage him to continue photographing them in embarrassing situations.
- Werewolf Dog reverting back to normal when he sees how miserable Cat is in Full Moon Fever. He turns down the Greaser Dogs' offer to join their gang, saying “he’s catbutt and proud!”
- It’s a Wonderful Half Life, full stop. The crowning moment definitely being when dream!Dog rescues dream!Cat from the Greasers and they run alongside a train to escape. Dog jumps onboard and stretches his arm out for Cat. It’s when they finally reach each other’s hands that their individual dreams merge into one.
Dog: Now I have a home. ♪Cat: And I've got a friend. ♪Both: And this is the way all dreams should end. ♬
- The final song.