Adored by the Network: Cartoon Network decided the pilot should become its own series, and the show has spanned four entire seasons without a single threat of having it yanked off the air, despite its scary nature. This show is also one of the few cancelled originals to still air on a regular basis.
After the show completed its four-season, 52-episode run (typical for most cartoon series on cable networks such as Cartoon Network and Nickelodeon), many fans petitioned for a continuation, which both the network and John R. Dilworth considered, but ultimately, Dilworth decided not to continue with any further episodes or seasons. On the same token, a (possibly theatrical) movie was confirmed to be in the works, however, it never came to fruition.
Adult Fear: Courage's parents get sent to Pluto and he's all alone until Muriel finds him.
Also, Katz is a fire engine red cat with purple stripes, Shirley the Medium is a green chihuahua, the Duck Brothers are bright blue with green, purple, and red eyes and neck markings, and there has been a chicken with an electric blue wattle (Although, to be fair, the chicken and ducks were from outer space. Maybe they're the fowl versions of Human Aliens?)
Ambiguously Gay: Di Lung. Dr. Vindaloo may or not also qualify, considering he had a quirk of shaving his legs and other body hair, back during a time when it was seen as effeminate.
Angry Mob: Eustace gathers one in "Courage Meets Bigfoot". When bigfoot reunites with his mother, however, they turn on him.
Aroused By Their Voice: Katz, captivating his victims with his smooth sexy voice before he, you know, kills them.
Arson, Murder, and Jaywalking: The possible candidates for Muriel's cousin Fred as imagined by Courage: A mummy, a giant bug, Frankenstein, and a mime (and THAT's the one he shudders about).
Ascended Fanboy: Michael Sporn, who wrote and animated the flashbacks for "Remembrance of Courage Past" was a big fan of John R. Dilworth's work, and likewise the series. At the same time, Dilworth was also a fan of Sporn's work as well.
Ask a Stupid Question...: Courage always does this with the computer, though he isn't really asking a stupid question, it's how the computer interprets it. Here's an example:
Courage: Computer. How do you get rid of bad eggplants? Computer: Throw them in the garbage. You twit.
Eustace; he once got dragged halfway across the world without him knowing it.
Important plot point: Eustace was cursed to be rained on until he showed generosity, and the rain got so bad that it was flooding the Bagge house and threatening to destroy it. So later in the episode, when Eustace loses his glasses, he looks at Courage and sees a young child (presumably himself as a young 'un, given the appearance) being rained on; he feels sorry for "the child" and gives him his hat, a selfless act that ends up stopping the rain curse.
Muriel is apparently deaf as well, "You know I can't hear without my glasses, Courage." Although that makes more sense when you remember that Courage has to rely on gestures to communicate.
Body Horror: There are quite a lot of episodes that have this. Especially most of Courage's screams which would result in this. However, the episode that provokes this the most is the episode "Cabaret Courage".
Carnivore Confusion: Done hilariously in the episode "Fishy Business", where Muriel serves sushi and raw fish for dinner - as Courage starts to help himself, a new goldfish the Bagges just happen to have now gives him a look of horror, causing Courage to change his mind. After the Bagges leave with the Fishonary, the goldfish hops out of the bowl, and appears to mourn over the sushi, before looking around, whipping out a pair of chopsticks, and happily helping himself to some.
The Cassandra: Courage, he always notices that something is evil, while Muriel and Eustace usually are ignorant of it.
Catchphrase: Usually using the same sound clip. Some like "The things I do for love!" and "What do I do? What do I do!?!" for Courage and "Stupid Dog!" for Eustace.
He has another one that tends to go something like "Something weird's going on here, or my name's <strange, non-sequitir, or just plain incorrect name>! ...And it's not."
Also, variations of "I'm not going to like this..." usually: "I just know I'm not gonna like this..."
Come Back My Pet: Courage routinely does this for Eustace, who routinely scares and abuses him. However, it's less out of the goodness of his heart and more because of his devotion to Eustace's wife Muriel.
Eustace: Did you break that door?! Courage: Ooooh, forget the DOOR!!
Conspicuous CG: The carriage from the mattress episode, the anvil from the precious duckling episode, and the rug in the living room. Most notable in "The Queen of the Black Puddle" where the Black Puddle Queen bumps her head onto the rug when trying to catch Courage and Eustace. Also King Ramses. "Hard Drive Courage" takes it to an extreme by having Courage animated in CGI when he first enters cyberspace- though here, it's justified: he's rendered in computerized graphics inside said computer.
Darker and Edgier: This could be disputed, as the entire series was darker than most other animated series; however, most episodes from the final season are significantly more dramatic in nature compared to other seasons, especially the first. "The Mask" is the best example of this.
Eustace is also a likely target. Unlike Muriel, he's also less likely to be saved from said monster or disaster.
Determinator: Courage himself. On the long run, he faced uncountable nemesis and supernatural weirdness, and yet he stands by Muriel out of feelings of love and gratitude. This is even more obvious on the Mega-Courage episode, where he squares-off against a robotic version of himself said to be better in everything. Despite getting brutally beaten over and over again by the robot, Courage just stays there, taking it all, and indeed that's exactly what enables him to win. Justified, as the one time he did run away from those he cared for, he lost them. Forever.
In "Revenge of the Chicken From Outer Space", the way Muriel is heard screaming after the Chicken captures her makes it sound like she's being raped.
In "Freaky Fred", it's quite easily to interpretate Fred's poem as ramblings of an insane serial-rapist. Plus the whole "locked in a bathroom" thing...
Double Subversion: Courage tries to defeat the Cajun Fox by putting a detour sign on the road so that he drives his steamroller into a bunch of rocks blocking the other road. He ignores it, thinking he's too smart for that, and plows over the detour sign plummeting off a cliff.
Downer Ending: In "The Great Fusili", Courage fails to stop Muriel and Eustace from being turned into puppets. Also, "Muriel Blows Up".
Dub Name Change: In the Norwegian dub, Eustace became Rasmus and Muriel became Matilda.
Early-Installment Weirdness: A number of the first season episodes have a lot of tradition cartoon antics (chases scenes, slapstick violence, etc), and can actually become quite goofy at times, with John Dilworth himself admitting a number of the earlier episodes were "cartoon filler".
Easily Forgiven: Courage, after Bigfoot causes him to splatter pie all over the kitchen. Muriel tells him that next time he should get a plate.
Easy Amnesia: Muriel and later Eustace in "Dr. Le Quack Amnesia Specialist".
Eldritch Abomination: That giant starfish that eats cities and won't stop until hearing Muriel speak.
There are a whole lot of these that show up on the show, really.
Eldritch Location: Nowhere. It's not very often the default setting of a show is one.
Even Evil Has Standards: Though he's not exactly evil, Freaky Fred's refusal to shave an animal's tail on the grounds that "it would be weird" definitely counts.
Everybody Laughs Ending: Not everybody, but a vast majority of the episodes end with this schtick of Courage, or whichever character, looking into the camera, and letting out a goofy and idiotic sounding laugh, before we iris out.
Everyone Calls Him Barkeep: Eustace Bagge is often referred to as "The Farmer" by characters on the show. The episode descriptions on Netflix exclusively refer to him as such.
Evil Albino: The Harvest Moon, although he's not really evil. He's more like Scary Albino.
Muriel: But my dear, we all must face reality. Kitty: Really? Like how you sneak extra sweets when no one is looking!? Muriel: (Gasps in horror and shame).
The show does a pretty good job turning a mad barber's obsession with shaving hair into full-blown horror.
The Fighting Narcissist: Bayou loves himself so much, he makes his slave slugs stuff shed skins of himself. His most used word is "me" and variations of it. He's so vain, that even when his stuffed shed skins attack him, he cannot bring himself to attack them.
Film Felons: A zombie "director" who was already a Serial Killer, who became an amateur filmmaker to lure in victims before he had died.
Flanderization: Arguably, Eustace Bagge. He has always been a greedy, selfish jerk, but he was mostly just annoyed and passive in the earlier episodes. In "Demon in the Mattress", he even follows Courage's plan to get rid of the demon inside Muriel (see Crowning Moment of Funny). He failed at first, but he did attempt to try again. Cut to one of the last episodes, "Ball of Revenge", where he tries to kill Courage by inviting all the major, and some not even that major villains.
For the Evulz: Most of the villains have some reason for what they do. Usually Eustace disturbs something that should not be disturbed. LeQuack has Greed, The Chicken from outer space is invading (at least the first time). Katz on the other hand is just trying to kill people for his own amusement (usually).
Freudian Excuse: Sure Eustace is mean, but he might be less so if his mother or older brother treated him better.
Funny Animal: Oddly enough, Courage does some very human-like things and can apparently talk (at least to the audience), but he usually gets treated as a normal dog. By comparison, there are several equally anthropomorphic characters, like Shirley, who get treated as humans without comment).
And Courage usually talked to other characters in the first season.
This is lampshaded in some small, throwaway moments. For example, at the beginning of The Last of the Starmakers, Courage is on the porch and picks up the newspaper with his hand before putting it in his mouth and giving it to Eustace.
Gypsy Curse: Shirley puts them on people who are rude to her. Though since she's actually not a mean person, she normally leaves a loophole to escape or undoes the curse if she feels they learned their lesson.
Fusilli the magician is turned into a marionette after mistaking Courage for a phantom and falls onto the stage.
The Flan King gets this twice in a row at the end of the episode.
This is Courage's preferred method of dealing with villains, rather directly or indirectly, but Big Bayou is one of the greatest, as not only was he beaten by his a spell from his own spell book, he was defeated by his own shed skins he'd had stuffed animated in part with his own venom. And to top it all off, he was so vain that he couldn't bring himself to attack his likeness. He was hoisted by at least three or four of his own petards.
The evil vet from "Remembrance Of Courage Past" also is hoisted by several of his own petards. Not only does the dog he emotionally tramatized for life ultimately defeat him, he does so using his own rocket. He is then further hoisted when the dogs he's been launching into space see him and decide to take their revenge on him.
The Cajun Fox spends his entire episode trying to put Muriel in a stew. In the end, he falls in his own pot.
Hollywood Heart Attack: Happens to Courage in "Night of the Weremole"; he clutches his chest and collapses during one of his wild takes. Then after he recovers in Dr. Vindaloo's office, he runs off with him, snapping the ECG leads and showing a Flatline.
Dr. Vindaloo: You almost bought it, boy. What is up with that?
Hypocritical Humor: Eustace always refers to Courage as a "stupid dog" even though he himself isn't aware of the dangers that goes around in Nowhere, and Courage is the one who usually has to save him and Muriel.
The aftermath of saying "no" to Flantasy Flan:
Eustace: What happened to you, woman?! You look like a house! Muriel: Well! Look who calls the kettle black!
It Makes Sense in Context: A majority of the plot devices fall under this. Most memorably, an episode which took place in an old west setting had Courage, who took the role as sheriff, bribe the military to send in a stealth bomber to drop a piano on a zombified outlaw.
Jerkass: Eustace (to a lesser extent) Courage's computer, Eustace's mom and brother, and Di Lung (the Chinese Punk Kid), whose catchphrase was "Watch where you're going, you fool!"
Jerk with a Heart of Gold: Eustace sometimes fits this trope but just in rare cases - see "The Curse of Shirley" where at the end he gives his hat to the "kid version" of him in order to protect him from the rain.
Karmic Death: The evil vet from "Remembrance Of Courage Past" is sent into space with his own rocket like he did to a huge number of dogs (including Courage's parents). For further karma, he finds himself surrounded by the dogs he launched into space who proceed to take their revenge on him. Additional karma is the fact the very dog he orphaned was the one who did this to him.
In Klub Katz Eustace, now a a wrecking ball, chases Katz through the island.
Eustace himself is a victim of this. A villain proving himself as a threat will target Eustace, not even knowing he or she is doing Karma's job.
Knight Templar: The Harvest Moon. Believing that Eustace is a poor farmer who doesn't respect the land, he demands that Eustace either prove his ability to grow a plant or leave his home. When Eustace refuses Harvest Moon tries to kill the Bagges.
Almost every character in the show has one. Muriel has soft piano music. Eustace has banjo and fiddle music. Le Quack's is french. Dr. Vindaloo's is Indian. Shirley's sounds gypsy. Cajun Fox has cajun music.
Sometimes, different characters share the same leitmotif. For example: The Demon in the Mattress and the Windmill Vandals share the same motif; Freaky Fred and the Evil Librarian share one; King Ramses and Mc Phearsom Phantom share one; The Great Fusilli, and the Paper Shadow Maker from "Profiles in Courage" and the disgruntled actor from "Cabaret Courage" share one; Basil the Burglar and Evil Weevil share one; among others.
On occasion rather loud accordion music can be heard from Muriel's radio.
Mama Bear: If Eustace is harassing Courage (or if it at least looks that way), Muriel is quick to bash him over the head with a rolling pin. With a One-Woman Wail.
In a few episodes, she has also expanded this to the Monster of the Week. For example, when she came upon Katz strangling Courage in "Katz Motel", she smashed a tennis racket over his head and saved Courage without a second thought.
Man of a Thousand Voices: Paul Schoeffler alone voices Katz, Cajun Fox, Le Quack, Freaky Fred, Dr. Vindaloo, Snowman, and many other one-shot characters. Just listen to all of them very carefully, they all start sounding the same after a while.
Meaningful Name: Eustace Bagge could be interpreted as 'Useless Baggage' which is what he is during most adventures.
While we're at it, Muriel Bagge could be interpreted as "merry old bag", since she's a perpetually optimistic old lady. And as for Courage's name, the fact that despite his cowardice he routinely risks his life for those he loves is extremely courageous (should go without saying). In fact, Muriel named him Courage because he showed courage (as seen in "A Remembrance of Courage Past").
Mood Whiplash: Masterfully. Depending on the episode, it switches from Tear Jerker or Nightmare Fuel to Funny in the blink of an eye. For example, there's the "Last of the Starmakers" for the former, where Courage saves the last batch of space squid babies, interspersed with moments of useless henchman and rollerskating military generals. For the latter, there is "King Ramses' Curse", generally regarded as one of the scariest episodes around, with a priceless jingle in the middle - "The man in gauze, the man in gauze, King Ramses!", and the man himself saying "Come onnnnnn" in the same tone as ever.
Vindaloo's inability (or unwillingness) to cure anything relevant to the plot (though to his credit he does give some advice about it). His academic title is pretty suggestive too: "Dr. Vindaloo, quack". And speaking of this...
The evil vet who orphaned Courage and sent a huge number of dogs into space For Science!.
A Running Gag is that when Courage confronts the villains, they rarely actually fight. Instead, they often decide who wins via some otherwise casual competition like handball or thumb-wrestling, made epic with with close-up shots of desperate, perspiring faces, Scare Chords, cutaways to the people in danger, and other devices to emphasize drama.
"Courage... Closer... closer... It would be lovely... If I could... have a cup... of... TEA!"