Angst? What Angst?: Pastis loves to play this up for dark humor. The deaths of characters rarely elicit any sort of grief (and Pastis has killed many). Various crocodiles, the roommate Leonard, and even Pastis himself have fallen victim to this.
Base-Breaking Character: Pig has resided in this position. For some, he's an endearing character whose innocence adds humor and heartwarming goodness to an otherwise dark and cynical strip. But for others, he's just an idiot whose stupidity becomes unbearable. It doesn't help that Pig can be frustratingly stupid and unclear at times.
Creator's Pet: Rat has a few shades of this. Though to be sure, Rat is..."liked", and to note, Pastis has stated that Rat is his evil alter-ego and he often lets Rat say things he wishes he could. So, a possibly Justified version.
Also, Orca. Ironically, Pastis decided to kill him off when he thought he was unpopular. By the time he realized Orca was popular, it was too late. Nonetheless, the character made one more appearance in an arc about baseball, with the usual explanation that he "un-died". Although, immediately afterwards, Rat states "I had to kick Orca off our team, because technically, he's dead." But then Orca returned once more in 2013 by devouring the killer dolphins.
Pastis has commented that he gets letters if Danny Donkey goes too long without appearing.
Speaking of which, many fans wanted Pastis to have the killer dolphins make more appearances (even after when they were eaten by Orca).
One of his Danny Donkey books has a group of Environmental Activists ask him to cut down on drinking beer, recycle, and he can help save the world. Danny replies, "Why? When the world is so full of lies and greed, why save it?". The Activists are awed by his speech and change the Save the World rally to a Destroy the World rally.
Fan Hater: Pastis claimed in an interview that he deliberately gets a rise out of these people. In response to angry letters, he sends them form letters of the "Thank You for Writing" variety, which only causes the complainants to send in more angry letters... in return for which he sends out more form letters...
"Funny Aneurysm" Moment: One strip featured a croc disappointed that Steve Irwin's head has never been bitten off, published just a few months before Irwin's real death from a stingray attack. Also, a fat joke about Ted Kennedy became much less funny after his death.
In a strip from an arc where Pig had Newt Gingrich as a pet, Rat said that Newt can never be president and John McCain is a lock for 2008. He was proven right about the former, considering Newt's dropout of the 2012 election, but wrong about the latter, considering the other nominee won that election.
Ever since the conception of Google+, let's just say that plenty of people on the Internet screamed Kill da Google! in unison.
Anytime Calvin & Hobbes was mentioned is now this (such as Rat saying he misses Bill Watterson) since Watterson guest-drew three strips in June 2014.
The treasury Lions and Tigers and Crocs, Oh My mentions that Pearls used to have more puns than it did at the time of the book's publication (2006) and even showed that Pastis nixed several strips in order to reduce the amount of them. Today, on the other hand, Pearls contains exponentially more puns than it ever did before.
In one strip, it's revealed that Larry the Croc has ordered pizza every night for several weeks straight and is given his latest for free. In 2015, Domino's Pizza started a similar deal, offering a free pizza after members order 6 pizzas online.
Pig's line in this comic, "Maybe we could just run blank space", takes on a new meaning since Taylor Swift released a song called "Blank Space" the following year. It's not helped at all by Stephen, in the previous day's strip asking the others if they know any good "prison songs".
In this comic, Rat says that he wants to build a 1000-foot tall wall from Washington to Maine to keep out Canadians, causing a Bait and Switch when Goat thought Rat was going to build the wall to keep out Mexicans. In the 2016 presidential campaign, Donald Trump decided to run for president, and declared that he was going to build a huge wall to keep out Mexicans.
Moral Event Horizon: Rat has crossed this once, when he killed a random guy, just to stop him from reproducing.
Rooting for the Empire: Based on the comments posted on the Go Comics website, many readers want the Crocs to catch and kill Zebra.
Tear Jerker: Surprisingly common. However, the infamous "Jerusalem bus" Sunday strip from shortly after Christmas 2003 is especially notable and absolutely soul-crushing, as is Pastis' commentary on it.
What Do You Mean, It's Not for Kids?: The main characters are all Funny Animals who make Incredibly Lame Puns on a regular basis. Perfect for kids, right? Then they start talking about current events and issues kids probably don't know about. And then there are the deaths. And the (albeit censored) swearing. And a bunch of other family-unfriendly activity. Yeah, this is one of those few comics meant just for older readers than all ages.
That said, though, Andrews McMeel, who publishes the book collections, have put out a few child-friendly "Pearls" books (a selection of kid-appropriate strips) through its "AMP! Comics For Kids" banner.
Ellie the Elephant (one of the Rat's characters) who really, really wants a grand romance with her apathetic boyfriend and goes overboard trying to impress him or to make a lasting impact on the world, but ultimately resigns herself to romance novels.
Andy, a dog who's left outside on a chain day and night and never gives up hope of seeing the world.
Jerkass Woobie: Rat, who's sometimes even proud to be a jerk, has had his heart broken by his love, Farina, and fails at doing anything that would benefit others. There are even times that he worries that he is a worse person than he thinks.