- In the episode "The Mask", Mad Dog is very explicitly a Domestic Abuser and some fans have argued there is even RAPE symbolism by the flower-pot. These undertones often believed to have ultimately got the series cancelled.
- Not to mention Kitty and Bunny seem to have a very close relationship, with several lesbian undertones that the writers barely try to hide. This was probably the nail in the show's coffin after everything else that happened in the episode.
- "Shadow of Courage" features a nasty old rich guy dying just off-screen, feebly calling out for his butler... who just walks away whistling jauntily and leaves the old guy to die. Sure, the guy had just fired the butler for no good reason, but that's pretty cold for a kids' show.
- From "Cajun Granny Stew": "That dog is starting to become a real pain in my a—" as the character sank into the water halfway through the last word.
- Though they only happen in Courage's head, we see Muriel get decapitated not once, not twice, but three times over the course of the series, complete with detailed insides. Eustace gets bitten in half at one point as well. To say nothing of Courage's frequent freak-outs that often end with his insides on his outside, so to speak.
- In the episode "Ball of Revenge", Eustace assembles a number of villains in his basement. Muriel upon seeing them asks what they're doing here Eustace responds:
Eustace: Err...it's a men's club.
Muriel: Oh, all right then. [sees the Lady From the Puddle] OH! This is one of those naughty men's clubs!
- "That Dam Beaver".
- In "Mission to the Sun," when the alien microorganism drills a tiny hole through Muriel's backside in order to enter and take over her body, she only feels a tiny sensation, which happens just as Eustace is walking by so she thinks that he just grabbed her ass.
- Everything about "Freaky Fred," as most of the episode consists of the titular character locking himself in the bathroom with Courage, then going off on a long internal monologue about how unforgivably "naaaauuuuuugghhtyyyyy" he's been. Granted, Fred's naughtiness refers to his tendency to shave the hair off of people and animals, but, this is Cartoon Network (home to a lot of original cartoon series that straddles the line between "What Do You Mean, It's for Kids?" and "What Do You Mean, It's Not for Kids?" and does a wide-legged split right on the line), and his fascination with shaving is heavily coded as a fetish, so insert any pedophile, sexual predator, or serial killer subtext about Freaky Fred here.
- "Hard Drive Courage". Courage and Muriel are using the computer to find a cure for Eustace's sickness, when Muriel suddenly presses one of the keys. Something show up on the screen (We don't see what's on the screen) which causes Courage to panic and quickly cover it up while suggestive music plays. Muriel covers her eyes and says she could use a cup of tea, then leaves with a smile on her face.
- The Computer asks Courage to press the key again. Courage gets rid of said key.
- At one point in "The Precious, Wonderful, Adorable, Lovable Duckling", Courage, Eustace and the duckling accidentally wind up in the bathroom, where Muriel is bathing, and they get called out on it by her. They respond by covering their eyes, but then the duckling peeks a little. Could fly past your head, since it's pretty subtle...until you see Courage slapping him for it.
- In the episode Hot Head, Eustace went into a building to help him grow hair. One of the questions the person on the speaker asks Eustace was "Whats 414 divided by 6?" The answer is never given in the episode but when one does put it in a calculator, they will get...69.
Radar / Courage the Cowardly Dog
Courage the Cowardly Dog's "crap past the radar" moments are, unlike most Cartoon Network shows, actually subtly put in, allowing for easy rewatching to catch the bits you missed the first time around.