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.
Ass Pull: In "Trading Places" Zoe's subplot looks like it's going to lead to some conflict between her and Penny when her crush Digby appears to be attracted to Penny. But it turns out he doesn't like Penny that way, even though he made it seem that way by his tone of voice when talking to her.
This wasn't a mistake by the writers, he was "pretending" to be attracted to her, in order to trick Zoe into coming out of her shell and speaking to him herself.
Blythe herself of all people is this. Some fans love her for her personality, design, and voice while others dislike her for being a Flat Character, mildly annoying, and so forth. Her human friends are also like this to some people.
Sugar Sprinkles, surprisingly, is now this after "Secret Cupet". Either you liked the episode and thought her love spells are funny, or you think she's a Karma Houdini whose actions in the episode were all sorts of wrong. Then there are those people who try not to blame the character for the writer messing up.
The Biskit Twins. Either you find their antics funny and endearingly incompetent or you think they're too mean-spirited or boring to appear in so many episodes.
Big Lipped Alligator Moment: "Blythe's Pet Project" has Blythe go into Sweet Delights looking for Anna Twombly's misplaced glasses. Once inside, Youngmee and her Aunt Christie launch into a bizarre vaudville musical number where all three get sucked into the lost and found box and find, among other things, the Holy Grail. Aside from an off-hand reference by Blythe in the next scene about musical theater, it's never mentioned again and has absolutely no impact on the plot.
"What Did You Say?" has Blythe trying to clear out her ears (she has a head cold) by sticking a towel in one of her ears, pulling it out the other and flossing back and forth. Not only is the gag quite a bit more... cartoony than the show normally uses, at least with human characters it is nearly always reserved for The Ditz in cartoons that do use it, to show how brainless they are, and Blythe is not that ditzy. It is never mentioned again and the rest of the episode treats her cold relatively realistically.
The "Humanarian" song number in "What Did You Say". It pretty much comes the hell out of nowhere, and is a series of eighties music video homages that don't have much to do with the topic.
In "Fish out of Water" when trying to find a way to cross the sewer, a bunch of sewer animals arrive, sing a song about building a boat out of junk, then immediately leave. Though this doesn't technically count, as the song is at least somewhat beneficial to the plot. But the fact the animals came the hell out of nowhere just to leave immediately after the song with barely an introduction. This feels like it should count.
The fact that the pets meet an actual alligator a few seconds later makes you wonder if this was done on purpose.
Broken Base: There are those people who thought "Secret Cupet" was funny or cute, or just try to ignore its issues, and those who think the episode was disgusting.
Die for Our Ship: Quite a few young Sepper (Sunil and Pepper) shippers have come to dislike Captain Cuddles and Delilah, even though the two characters were very nice to the main pets and were only one shots who probably won't make another appearance.
Mrs. Twombly is this to some extent. It helps that Kathleen Barr, the voice of Trixie from Friendship is Magic, voices this character. Even better is her crazy cleaning fever season during "Eve of Destruction" that gained her more popular status.
The Biskit Twins' butler, who gets his groove on during a musical number in "Penny For Your Laughs", gets noticeable love from YouTube viewers.
The Biskit Twins themselves got a rather popular fanbase, mainly due to their ambiguous background story and humorous character.
Out of all the guest pets Madame Pom, Shahrukh and especially Sugar Sprinkles are the most popular.
Family-Unfriendly Aesop: Episode 5 shows us that spending time with people who aren't the same as you will turn you into a mean spirited bitch, that it's ok to turn on your friend if they're also friends with someone you don't like and that people you don't like don't deserve second chances.
"The Hedgehog in the Plastic Bubble": If you become paranoid thinking you're going to die from a fatal disease you learned off of the internet which is 100% accurate all the time Don't bother telling your parent(s) right away, none of their business... instead let the paranoia fester until you become a complete delusional basketcase. THEN tell an adult. See Idiot Plot below.
What's in the Batter?: So you've lost an accessory...for suffering such a loss, it's perfectly acceptable to sabotage your friend's business, demand your friends rectify your own mistake, crash someones else's party, sabotage said party and physically assault the hosts unprovoked.
Fan-Preferred Couple: A minor example here. Most fans are generally very blasť toward Josh. And since episodes like "Summertime Blues" and "Eight Arms to Hold You", some believe that Blythe actually has more chemistry with Russell.
And then there's Youngmee. Holding hands frequently, cuddling their heads next to each other, etc.
Vinnie and Sunil, due to their Ho Yay-like friendship.
When Zoe Trent was revealed, comparisons to Twilight Sparkle were instantly made, while Twilight herself reminded many of Anarchy Stocking. Plus it's made funnier when certain fans imagine Princess Celestia using the royal canterlot voice and being as hammy as possible but as a diva.
Humor Dissonance: In "Lotsa Luck", Old Bananas is treated by the pets as the funniest thing in the history of forever, in spite of his humor hardly being funnier than that of Pepper's.
Idiot Plot: In "The Hedgehog in the Plastic Bubble" Blythe has much less common sense than she normally does in order for the plot to work.
In "A Night At The Pawza", Fisher would have succeeded if he used his money and influence to bribe a "real" licensed building inspector to do the job, instead of a mook pretending to be one
Jerkass Woobies: The Biskit Twins are this to some fans. "What's in the Batter?" just emphasizes their Woobie status after the pets crashed their relatively tame party. "Bakers and Fakers" also boosted their Woobie status at the later half of the episode being publicly humiliated during the judging of their cakes.
Vi from "Penny for Your Laughs" after Blythe inadvertently hurts her feelings.
Blythe's embarrassing laugh, also from Secret Cupet.
Blythe and Youngmee's fangirl squeals.
Out of Order: "Winter Wonderland Wha...?" honestly seems like it was meant to be closer to the start of Season 3 which would justify why Blythe never questions Francois's return sooner. Though it could just as easily be the writers fixing the plothole at the last second.
"Winter Wonderland Wha...?" was likely supposed to come before "Two Pets for Two Pests" as Whittany and Brittany didn't bring their chinchillas with them and Francois has already been rehired.
The Scrappy: Penny Ling's ego can get annoying for some viewers. Especially in "Back Window" when it gets Russell and later all the other pets injured.
Penny Ling after Pepper's "jokes" about her. Taken up a notch in an episode of Penny repressing her own feelings about a man suit she assumed was her outfit for the ball. And once again after Zoe and Pepper getting into a fight on whose party theme is suitable for her.
Vinnie after going into a Heroic BSOD in "So You Skink You Can Dance"
Blythe during the episode "Helicopter Dad", especially when she breaks down crying after telling her dad to leave her alone.
Zoe Trent on the latter half of "Terriers and Tiaras".
Sunil in general can be seen as this. His magic tricks often blow up in his face and he's pretty much a Nervous Wreck. Taken up a notch in "Lights, Camera, Mongoose!" and as of season 2, he's been washed down a river, nearly drowned and recieved unwanted fame in the Meme episode. On top of this, Blythe referred to him as "Worrying Mongoose" once he became a famous meme instead of his own name which probably depressed him. Then there's future episodes like "Super Sunil" and "Sunil's Sick Day" which will most likely make him an even bigger woobie than he already is.
Ollie in "Eight Arms to Hold You", with his story of how he arrived in Littlest Pet Shop serving only to exemplify how pitiful his existence is.
Sweet Cheeks from the episode "Pawlm Reading". He oozes Moe to such a degree that he even rivals Penny and Sunil and on top of that, he's a poorly socialized Shrinking Violet, cooped up in his owner's purse who is scared of even touching grass. Also, his Phony Psychic owner assumes he loves nummy nuggets which he hates.