Animation Age Ghetto: It was produced by Nickelodeon, a channel that prided itself on being a network "for kids, by kids", but regularly dealt with topics that only adults would understand, such as home ownership, holding a job and dating.
Ass Pull: Played with in "Manic Mechanics". Rocko breaks his car, and all seems hopeless....until he notices a "Broken/Fixed" switch on the engine.
Big Lipped Alligator Moment: Tends to happen fairly regularly, but possibly the most notable instance is the scene with the naked fairies and the shaved voyeur gopher in "A Sucker for the Suck-O-Matic".
Heffer being abducted by aliens who look like him in the episode Cruisin. Even though they went into the Bermuda Triangle and went through a time warp, this makes no sense in relation to the rest of the episode.
Also, the following exchange in "Bye Bye Birdie":
Heffer: Hey Rock, do you want to move to France? (not taking eyes off TV)
Rocko: Not really. No. (eyes also glued mindlessly to TV)
Heffer: Yeah, me neither. (and they just continue watching TV)
Though they don't move there, Rocko and Heffer do go and visit France in a later episode.
Cargo Ship: Canon: Spunky's forbidden romance with a mop.
The Psychiatrist was shown later to be wining and dining said mop.
And how does Spunky get over it? He falls in love with a fire hydrant!
Cult Classic: The show was never quite as popular as The Ren & Stimpy Show or SpongeBob; the best it could manage was this. (The cult fanbase, though, was enough so that the show was on MTV for a brief while.)
Growing the Beard: Not that season 1 wasn't good or anything, but the show really began to shine in season 2, many agree that season 3 is the best season the show ever had. The show becomes more of an ensemble comedy, with episodes focusing on Heffer, Filbert and the Bigheads.
"Heff in a Handbasket," The episode where Heffer sold his soul to be on a game show, was once pulled due to its blasphemous content. Eventually, the episode did air again on June 6th, 2006 (6/6/06) on Nicktoons TV. Guess the Nickelodeon censors didn't see why would this be inappropriate.
In one episode, Filburt has a tube of a toothpaste-like substance called "Spirit Away". It's also funny if you're a Touhou fan, as Ran has a spell card called "Yukari's Spiriting Away".
One episode features Heffer choking to death, and the Grim Reaper comes and mockingly tells him he was killed by his own gluttony. Heffer cries, "I'M A GLUTEN!!!" This was a good long while before the anti-gluten diet craze.
So Cool, It's Awesome: Even as a "short runner" (or considered short in comparison to some of Nickelodeon's otheranimatedshows), this show remains one of the '90s most universally well-liked cartoons. The fact that it never experienced true Seasonal Rotnote (though some will say that, out of the four seasons, the last one was weak compared to the first three and then there's the whole thing about Joe Murray not being involved with the show after his wife committed suicide and blaming himself for not being there for her), had mostly likable and sympathetic characters and its clever writing/humor which only becomes funnier with age also helps.
Squick: The end of the episode "The Fatlands", not only does Dr. Hutchinson give Rocko all of the fat that she sucked out of Spunky... Heffer ends up eating that fat!
They Changed It, Now It Sucks: Though it doesn't affect the show as a whole, most people agree that the original theme song from season 1 was better than the B-52's version.
What Do You Mean, It's for Kids?: Aside from the hidden dirty jokes and crude humor (some of which has been cut from reruns), the show's deals with themes you'd find on adult cartoons like The Simpsons (back when it was the sitcom to watch to laugh at jokes about how hard modern life can be), such as home ownership, trouble on the job, infidelity, immigration, racism (shown as "animalism" on the show), death, cults, and love/dating.
It could be argued that it wasn't really made for anyone: in the early days of cable television (about the late 80s to the mid 90s), producers had no idea who had it or what viewers expected of it, aside from niche programing that wasn't offered on network television. It wasn't until reruns that it was officially labeled a kids' show.