Acceptable Targets: There is an ancient mystical tome in the ghost realm called "The Book of Annoying Beings." The Ghostbusters are on one page. As the Ghostmaster rips it out in frustration, we see that the very next page is devoted to mimes.
Several pot-shots are taken at New Jersey. Understandable, considering the show takes place in New York.
The essential idea was to create a show that was acceptable for Saturday mornings, but would still get the same Multiple Demographic Appeal that the movie had, which is why you have unusually solid (and complex) writing and humor (with examples like "The Thing in Mrs. Faversham's Attic" or "The Hole in the Wall Gang"), episodes with near-psychedelic visuals like "Knock, Knock" and, uh, a bit of occasional "focus" on Janine. Unfortunately, since The Merch sold like crazy, the executives saw only dollar signs, and demanded Re Tools to try and sell more merch. The writers revolted, many (including JMS) left and the show went right back into the ghetto. (Ironically this also drove away the wee kiddies to shows like, well, He-Man and the Masters of the Universe (1983) since the uniqueness of the early show is what drew people to it in the first place.)
Anvilicious: Fourth season episode "Follow that Hearse" really wants you to know that pollution is very, very bad.
Big-Lipped Alligator Moment: At one point in "Banshee Bake A Cherry Pie", we get a scene of a lovestruck Venkman dreaming he's in a music video with a singer (actually a banshee) he has a crush on. Egon appears, interrupting the performance and then breaks the fourth wall as the scene ends.
Egon: "Uh hello, I'm Dr. Egon Spengler and you're not watching this overblown spectacle. It's totally in the banshee-riddled mind of my colleague here. Um, thank you."
Complete Monster: The Grundel (who later returns in Extreme Ghostbusters) is an evil spirit who enjoys corrupting children. He has minor Compelling Voice powers: If a child has history of bad actions and is getting into trouble all the time, the Grundel can often convince the child to invite him in, after which the Grundel will convince the child to commit more bad actions. The more bad actions the child commits, the more the child falls under the Grundel's influence, eventually turning into a Grundel themself and looking for more kids to corrupt. In season 3's "The Grundel," he convinced a child named Alec to tamper with the Ghostbusters' proton packs during a school assembly, endangering all the other children present. The Grundel also manages to convince Alec to bring his brother Lee to him so he can corrupt Lee as well, despite Alec's initial protests. When Peter Venkman tries to save Alec and Lee, who are hanging off a ledge at a dangerous abandoned warehouse that the Grundel had lured them to, the Grundel tries to prevent this, stating "If I can't have them, neither can you!"
Creator's Pet: Arguably Slimer; he was The Scrappy to a lot of viewers, so what did the producers do? Rename the show Slimer and the Real Ghostbusters and have him show up even more. Then there were the Junior Ghostbusters. Yeah.
Slimer was at least a little more bearable when he genuinely helped the Ghostbusters save the day, like when they went up against Killerwatt.
A large part of the problem was that Executive Meddling changed Slimer's character. Originally, Slimer was an affable sidekick that didn't speak coherently. While there were episodes where he would play a major role, there were others in which he barely appeared if at all. However, with the third season, Slimer started to take more focus in plots and began speaking coherently.
Franchise Original Sin: Many fans dislike the later seasons for having Peter be nicer to Slimer, though even the earlier episodes occasionally implied that Venkman had a hidden soft spot for the spud and he would sometimes cut Slimer some slack in spite of the misery he caused him. At one point, he even sneaking Slimer a pizza while demanding that he keep quiet about it.
"Funny Aneurysm" Moment: There are numerous examples of Egon being oblivious to Janine's feelings for him. Funny at the time, not so much when you watch "Janine, You've Changed" and see what it led her to.
Janine:[to Egon] It's your fault! All of it! I did it for you! I wanted to be prettier so you'd notice me, and you never did!
Harsher in Hindsight: The episode "Janine's Genie" has one scene in which the Ghostbusters, including Janine, tries to prevent a ghost-hijacked plane with the passengers inside from crashing in New York City. Janine and Peter, piloting the plane themselves, nearly avoided crashing against the WTC twin towers.
The story goes that Lorenzo Music was dropped because Bill Murray was concerned about Peter Venkman sounding like Garfield and executives sought to accommodate him. If indeed true, well, that makes a later Murray role very ironic.
Speaking of Garfield, Frank Welkernote Voice of both Ray and Slimer. would later go on to replace Lorenzo Music as Garfield after his death, Starting with The Garfield Show onwards.
In "Revenge of the Ghostmaster", the titular spook taunts the Ghostbusters using his own personal television channel, GMTV - no relation to the British breakfast-time show which started a few years later.
Episode 105 involves the Queensborough Bridge being attacked by Trolls, which takes on a whole new meaning nowadays:
Peter: "It's Monday morning. Where else would trolls be but the Queensborough Bridge?"
In "Janine The Ghostbuster", Janine that she should go into business for herself. In the IDW comics, she's now the leader of The New Ghostbusters.
In the season 2 episode "Egon's Ghost", a Freak Lab Accident destabilizes Egon's molecular structure, turning him into, for all intents a purposes, a ghost, even though he's still alive. The side-effects of this half-ghost state include permanent intangibility, turning invisible at will, and, for no explained reason whatsoever, the ability to sense ghosts. This would later become the entire premise of the iconic ghost hunting show of the next generation.
In the episode "The Mean Green Teen Machine", Winston dreams that he's in a parody of Star Trek: The Next Generation, where he plays the role of Jean-Luc Picard. Years later, another Star Trek series would give us our first African-American Starfleet captain Benjamin Sisko, who even becomes bald as the series progresses.
The opening to the show features the Logo Ghost walking the streets of New York... without revealing spoilers this might remind some people of the climax of the 2016 reboot...
Jerkass Woobie: Peter Venkman is a bit conceited and abrasive at times, but he had a rough childhood and it's easy to sympathize with his anger at Slimer if you happen to hate the spud, too.
Memetic Molester: The Grundel has this thanks to his unsavory obsession with manipulating children. Many people even assumed he was meant to be a stand-in for child molesters.
Narm: As Phelous points out, Dave Coulier's portrayal as Peter Venkman from season 3 onwards is very cring-worthy due to how he delivered Peter's dialogue as if he was brain dead. Even worse is when the studio redub older episodes that originally had Lorenzo Music as Peter, taking away the humour out of Peter's one liners.
The Junior Ghostbusters, a trio of kids that came with all the Executive Meddling to make the show Lighter and Softer. None of the writers were thrilled with using them. JMS even once recalled saying he'd only use them if he could run them over with a truck. The kids only appeared twice here (though with expanded roles on Slimer's own cartoony spin-off), but fans were still irritated because these two appearances took up screentime from the Ghostbusters' re-matches with fan favorites the Boogieman and Samhain, respectively.
Slimer also has a lot of detractors for being little more than comic relief and barely doing anything to benefit the plot. It didn't help that the later seasons gave more focus on him and even renamed the show as Slimer! and The Real Ghostbusters.
Seasonal Rot: After the syndicated episodes, Seasons 3 and 4 suffered from Executive Meddling to be Lighter and Softer (as well as replacement voice actors for Peter, Winston and Janine), but still had some fan-favorites. Season 5, however, awkwardly shoehorned in elements of the second movie. (Louis was one thing, Janine getting a second makeover to give her the hairstyle of her movie counterpart was another thing, but the city's injunction against the team was seen as forced.) Slapstick humor became even more apparent and a number of episodes saw a Two Shorts format instead of one story.
Some Anvils Need to Be Dropped: The show was very rarely everAnvilicious in any sense; "Janine, You've Changed", however, has a rather blunt anvil about not needing to worry about your appearance and weight and whatnot and trust that people will like you just the way you appear. And if you're at all familiar with the history of "youth beauty" and anorexia in the 80s and early 90s, that anvil seriously needed some dropping on the show's largest age group.
"The Bogeyman is Back" boils down to there's nothing wrong with admitting being scared. Maybe it's laid on a bit thick, but considering the target audience, it's a very valid message.
Strawman Has a Point: Anytime Peter complains about Slimer. In "Slimer, Come Home," he condemns Slimer for eating "anything that's not nailed down or on fire." In "They Call Me MISTER Slimer," he points out Slimer is responsible for a lot of bills that he doesn't have to pay for.
Tear Jerker: The ending to "Drool, The Dog Faced Goblin".
Ray trembling and audibly trying not to cry as he quits the Ghostbusters in "Look Homeward, Ray" is heartbreaking. Props to Frank Welker for making Ray genuinely sound like he's seconds away from breaking down.
Ugly Cute:Slimer. The spud was actually pretty likable until he got overexposed in the later seasons.
The Woobie: Slimer in some of his focus episodes, especially in "Slimer, Come Home", where he runs away and leaves a letter telling the Ghostbusters that he can't bear to stay with them if he continues causing them trouble.