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.
And of course Cars 2 had a brief scene with Polyrhythm by Perfume.
Base Breaker: Mater. While children seem to love this character, most other people despise him. There's pretty much a consensus that he ruined (or at least severely hurt) Cars 2. There is also a subset that will Take a Third Option, finding him tolerable in the first movie, but obnoxious in the second.
Big Lipped Alligator Moment: When the paparazzi find Lightning in Radiator Springs and shine a spotlight on him, Mater yells "It's the ghost light!", and the movie makes no reference to this and no attempt to explain what he's talking about. Slightly played with in that this is actually a reference to a short that comes with the DVD, but if you're watching it in theaters or on TV this context is removed.
Broken Base: Cars is easily Pixar's most divisive film. Those who like it find it just as good as any other Pixar film, those who dislike it consider it a dumb concept and Pixar's weakest film. There are also those who like it despite it not being Pixar's best. Cars 2, while it has it's fans, was generally considered to be bad.
Cars is considered to be one of these. It's easy to imagine a little counter in the corner dinging kinda like Cinema Sins whenever you see a Pixar cliché. Stranger in a community or group? Check. Brooding moment from a side character? Check. Wacky sidekick who forms a comedic duo with the main character? Check. Said group full of wacky members with their own quirks? Check. All of the development threatens to go downhill when something happens to separate or alienate the stranger? Check. They all decide they like this new stranger and want him back in the group? Check. The stranger decides that s/he really is a member of the group? Check.
One of the major complaints about the sequel is the fact that the Cliché Storm element is taken to nigh painful extremes. The clichés were even more evident in Cars 2 because they were using action-movie clichés too, more notable than simple Pixar clichés.
To more conservative viewers, the sequel's "once big oil, always big oil" message might come across as one.
Something to dislike on both sides of the spectrum as the Aesop can also be viewed as alternative fuel is an evil scam.
In addition, as far as the friendship between Lightning and Mater goes, Cars 2 can come off as, "Be yourself, even if your true self is a jerk who constantly embarrasses everyone around you and creates big setbacks for your friends."
Connect Doc's "they quit on me" speech with the fact that this was one of Paul Newman's last major roles.
Narrowly averted in Cars 2: The weakness/trigger of the new fuel was supposed to be radiation but after the nuclear power plant meltdown in Japan they changed it to radio waves (as of John Lasseter's "Day in the Life" documentary).
One of the supporting characters is a diminutive and lovable forklift named Guido... damn you Jersey Shore...
Back when the first movie was released, MAD did a spoof that mentioned (among other things) that they cut an appearance by the "Popemobile" at the last second. Well, guess what actually appears in the sequel...
In the sequel, Mater puts together quite a day out for his best friend when he comes home, and even tries to infiltrate Lightning's date with Sally. They have a secret handshake that a bystander notices gets longer every time they do it. If that's not bad enough, at one point Lightning chases after Mater repeatedly yelling "You're the bomb." Yeah...
Fillmore and Sarge have lots of this. Despite their clashing personalities, the two are almost inseparable. The two are almost always next to each other, Sarge is even shown sleeping next to Fillmore in "Unidentified Flying Mater". Twice. Some of the toy packaging go as far as describing the duo as being "Unable to live without one another."
Lots regarding the sequel, going from diehards saying that the film only seems bad in comparison to the rest of Pixar's work (and calling any and all critics of the movie "haters" who are gleeful that Pixar has finally produced a genuinely bad film) to persons who actually are gleeful that Pixar has finally produced a genuinely bad film (and wasted no time in rubbing it in the noses of said diehards).
Quite a few Pixar fan's reaction to the dual announcement of The Incredibles 2 and Cars 3 was "YES! Incredibles 2! But WHY THE HELL are they making another Cars movie?!"
Jerkass Woobie: The Lemons themselves from the sequel. They might have done many wrong things, but it is hard not to feel sorry for them when they were made outcasts by the others.
Moral Event Horizon: Chick Hicks, the film's antagonist, was already bad due to his dirty racing tactics, but at the end when he purposely runs The King off the road — causing his crippling crash — and has no remorse for it, he unsurprisingly loses all his fans.
A deleted scene in the first movie shows a discarded scene which involved, while getting lost trying to find Mack, Lightning McQueen wandering through a car graveyard full of rusty and destroyed cars. The scene seems reminiscent of Snow White getting lost running from the wicked Queen and it's not hard to figure out why the scene wasn't in the final product.
Also the fact that they based King's crash off an actual crash Richard Petty was in at the Daytona 500 might count. Sure it's bad enough the cars are alive in this movie, but the fact that an actual person had to go through that... sure, he made it out okay, but still...!
Some of the Family-Unfriendly Death in the second movie. Special mention must go to the death of Rod "Torque" Redline, who gets tortured for information by the villains, and then blown up. While his actual death is partially obscured as a reflection on a screen that's showing a picture of Mater, we get to see the explosion and the flames rising from his body. Not helped by the fact that it underscores an aversion of Never Say "Die".
In Paris, Mater comes across a car that has its eyes in its headlights instead of on the windshield (a possible Take That toward previous depictions of anthropomorphized cars). Mater (and the audience) are suitably horrified.
Viewer Gender Confusion: Two race cars, one pink, one blue. One's a boy, and the others a girl. And it's not the ones you're probably thinking of. Family Guy did do this gag years before, but it was a parody of the Chevron claymation car commercials that aired in the late 1990s.
The Woobie: If you notice very hard in the "Our Town" sequence, Mater had a coat of sky blue in the flashback. When customers stopped coming to Radiator Springs and business closed and all the cars are looking at the empty road, the first car to leave in disbelief is Mater. Plus, he is the one who has physically changed the most- not a hint of paint left on him. And in the present, he's probably the most crazy of the bunch. Evidently, he took the by-pass the hardest.