These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Anti-Climax: Bigby and his children meet again after five years and their reunion gets no focus at all?
The sheer speed by which the Fables disable the Adversary's Empire was off putting to many, considering for how long the Empire was held as this vast all powerful menace. While this may be a brilliant subversion of the unbeatable Empire and the Sauron-esque Evil Overlord tropes by showing how politically fragile it would be (it has many of the weaknesses that real world dictatorships have), and how Muggles Do It Better when it comes to heavy weaponry, it can still seem disappointing.
The actual Deader than Dead end of Mister Dark might seem this way given the Deus ex Machina way he is finally destroyed. However, given that there was a suitably epic battle between him and Frau Totenkinder, most readers will forgive the way the unstoppable threat he represented got ended so quickly by Bigby's father, the North Wind, especially given the Tearjerker way it happens.
Jack of Fables introduces characters who are essentially gods of writing tropes and are the creators of the fables, which would cause a huge existential crisis to the community. This factor is not explored in the slightest when Bigby and Snow meet Mr Revise and at the end of the crossover their memories are erased.
Awesome Art: James Jean's covers were striking, emotive and haunting, and for which he won 6 consecutive Eisner Awards for Best Cover Artist. It's likely he could have pushed his streak further if he hadn't retired from the comic book industry
Big Lipped Alligator Moment: The story where Bigby has to save one of his sons from being attacked by monsters (revealed to be his brothers). The battle's narration stretches quite a few lines, apparently causing natural catastrophes hundreds of miles away, making mundy's go insane and.. causing two-headed cows to be born? ... what? It also makes Snow see The North Wind the same way Bigby sees him, resulting in her calling him an "evil old man." Cue the end of the chapter however, and, with the exception of Bigby's brothers being introduced as minor roles in the story, none of this is ever mentioned again.
Complete Monster: When Hansel and Gretel were captured as children by Frau Totenkinder, who was trying to sacrifice their lives to demons for youth and power, they fought back and burned her alive in her own oven. Hansel found he enjoyed the sight of watching witches burn. With this new-found bloodlust, Hansel set out to make as many witches suffer as he could, not caring that all too often, victims of his witch hunts were innocent girls. Hansel subjects them to torture and deaths for his own gratification without a twinge of remorse. His crowning moment of evil is after he discovers Gretel had been taking an interest in magic. He murdered her on the spot before fleeing the Fable community to align himself with their great adversary as his Inquisitor general, putting himself in charge of hunting down those who might prove disloyal to the Empire. Hansel is one of the Empire's most feared and zealous leaders who uses his position to satisfy his need for torture and domination.
The novel Peter And Max gives us Max Piper. He is always a dark one, with extreme jealousy toward his brother Peter. However, when Peter receives their father's flute Frost, Max becomes nigh on insane...he carelessly kills innocents when the Adversary invades, and later on actually uses a spell to sterilize every other Fable. The devastating Spanish Influenza epidemic that killed more people than the First World War was simply a side-effect of the Fable-sterilizing spell, but one he's absolutely delighted to watch in action. He also has no qualms stealing children for the whole Pied Piper incident and later brags to his brother that he "used them to pay off debts." He smugly adds that the kids didn't die happy...
Genius Bonus: Plenty of the characters who are not explicitly named or only slowly implied. Not to mention; in the first Jack of fables book, we see a black janitor named "Sam" who doesn't seem to remember where he is. By the end of the book, he starts running very fast and we see that the tigers had been turned into butter, and Revise shouts that he thought he had him censored - who's he talking about? Little Black Sambo.
Even more hilarious in that the real life version was an epic-level flop, as opposed to the fictional versions' record-shattering success.
Hollywood Homely: A subversion with Mrs. Sprat who is very fat and very homely, and also a Perpetual Frowner and Battle Axe Nurse. In Fables #100, Snow White calls her on the fact that she is both ugly and mean, and that is why no one likes her. In a "The Reason You Suck" Speech moment, Snow explains that she herself is beautiful but can be quite a bitch at times, but her beauty lets her get away with it. Likewise, a woman can be ugly as sin but have a pleasant and charming personality, and that will let people get close to her. Since Mrs. Sprat is both ugly and mean, she needs an attitude adjustment before she pisses off the wrong person.
Could be considered to be played straight eventually. In the beginning Nurse Spratt had a much more cartoony and haggard appearance. When she became a bigger part of the story, while she didn't look as pretty as the other female fables (not yet, anyway), her appearance was a bit less exaggerated.
This may also be attributed to the fact that Mark Buckingham was given more of a chance to add detail to her facial expressions since she had more panel time devoted to her than previously, where she was either a wordless background character or a minor character with a couple of word balloons.
Idiot Plot: Inverted; almost every character seems to be hyper-competent and highly articulate. One explains this by pointing out that even the world's greatest human in a given field still has only a lifetime to practice, and the Fables have had several hundred years and counting.
Jerkass Woobie: Spratt falls into this, when she is seen the only fable left on the arm, crying to herself as everyone else had literally left her to be killed by Mr. Dark. Of course, Spratt isn't exactly nice, and the Fables themselves aren't exactly shining paragons or morality either.
Bigby was this even before he pulled a Heel-Face Turn and left the Homelands. His backstory shows just how miserable of a life he had before he went bad.
The Adversary aka Geppetto. Bigby has his moments as well.
Frau Totenkinder has elements of this with how she deals with Yusuf's attempt to use the djinn against them, and fully confirmed if one suspects that she correctly anticipated how the North Wind would react to the discovery that one of his grandchildren is a zephyr.
Some consider Jack taking advantage of an emotionally devastated Rose Red in order to have sex with her in The Great Fables Crossover to be the point where he stops being the guy you love to hate, causing the reader to just hate him instead. On the other hand, given his treatment of the Snow Queen, he was a villain nearly from the very beginning. His worst act may have been selling his own son to demons to save his own skin.
Totenkinder sacrificed every child on the planet to fuel her own power against Mister Dark in The Unwritten crossover.
Hansel murdering Gretel certainly counts, though he may have crossed it even earlier with his countless witch burnings.
Bigby Wolf in his origin story. A wolf bigger than a clydesdale horse. Half its mouth is covered in blood. Standing on top of knights, soldiers, and civilians eaten alive in a gory burning field. Looking the reader right in the eyes.
What Totenkinder engineered to happen to Yusuf.
One cover featuring witchhunter Hansel drowning two women.
In the Fairest spin-off, Rapunzel's Dark and Troubled Past shows that basically the legend of Sadako happened to her. Her time spent down the well, and her insane rampage when she crawls out of it, come straight out of a horror story.
Tear Jerker: "A Frog's Eye View" from 1001 Nights of Snowfall.
Boy Blue's death, and the wake that follows with nearly every single one of the fables mourning.
Darien's death in "Cubs in Toyland". It really hits hit home when right before sacrificing himself, he cries and asks why he has to die when he's still just a kid, who never got to do anything yet.
What an Idiot: Tommy Sharp who suspects that the citizens of Fabletown are vampires. He decides to go right up to them and say that he thinks they are immortal vampires.
What Do You Mean, It Wasn't Made on Drugs?: Bufkin's own story arc "Revolution in Oz" starts out weird and only becomes weirder and weirder till it borders on down right bizarre, to the point you wish you were rather reading "Alice in Wonderland". Though if one is familiar with Oz... some tropes may be surprisingly familiar.