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.
Alternative Character Interpretation: Calvin's general obliviousness to the world around him, intricate, vivid fantasies and general inability to comprehend the motivations of other people are all consistent with descriptions of autism (or schizophrenia).
Who or what exactly Hobbes is tends to be a subject of debate. Many fans still believe that he's a figment of Calvin's (possibly demented) imagination, in spite of Watterson outright saying that wasn't it (backed up by things Calvin couldn't have done himself, such as getting tied to a chair). It probably doesn't help that by Watterson's own admission, the comic goes out of its way to not explain it while at the same time raising more questions.
Calvin's mother can come off as harshly authoritarian at times. She rarely smiles at him, and has a knee-jerk reaction of trying to suppress whatever he's engaged in (granted, she often turns out to be right to do so), while his father tends to be more lenient. When you consider that Calvin appears to have every standard symptom of ADHD and doesn't seem to be getting any treatment, this can have mildly abusive/neglectful overtones. Watterson himself lamented in one commentary that he regrets that the strip mostly shows her in a bad mood, since most of her appearances show her reacting to Calvin's latest misbehavior.
Calvin, in his exuberant sled or wagon rides, frequently flies off what seem to be massive cliffs, falling heights likely to cause death or serious injury. Either Cartoon Physics are in charge, or the strip is an Unreliable Narrator and the cliffs shown are only his perception of smaller and less lethal cliffs. Similarly, his backyard may be less than the vast national park it seems to be, which would explain why his father treks the family hundreds of miles to go camping rather than do it out back.
In the story arc where he accidentally pushes his mom's car into a ditch, he reacts as if it was a cliff, indicating that he does exagerate greatly, and his stunts are showing what he imagines around him, not what is actually there.
A few fan interpretations of the infamous Noodle Incident are to be found floating around the internet. One of the most popular is that in this case, Calvin was actually innocent for once, and really was framed, as he claims.
Anvilicious: Watterson's frequent broadsides against TV, advertising, comic books, deforestation, commercial culture, and humanity can get ham-fisted at times. He himself admitted to being too heavy-handed in an arc in which Calvin and Hobbes go to Mars to escape pollution, only to encounter a Martian, and realize that they have to take care of their own planet before going on to others.
Americans Hate Tingle: More like Everyone Outside the English-speaking World Does Not Understand Calvin And Hobbes: While still beloved in its native U.S. as well as in Canada and the UK, outside those countries it never reached the same popularity. Calvin is most often remembered abroad as that (American) kid who pisses in the tyres. The fact it doesn't have an animated adaptation due to his creator's strict policy about marketing doesn't help.
In Brazil, at least, Calvin & Hobbes' books are regularly sold, translated into Brazilian Portuguese, in bookstores and newspaper stands. While the strip is not super famous it is well known here. Unfortunately, so are the stupid stickers of Calvin pissing on things.
In Portugal, it is also well known and cherished, especially for those who were young adults, teenagers and kids in the 90s (to the point that the newspaper, which was still in its infant years, was bought solely for the comic strip). And most people don't know about the stickers, which is a good thing.
Breakout Character: Watterson had no plans for Rosalyn beyond her initial story arc, but quickly realized the way she could completely intimidate Calvin, unlike any other character, offered a rich vein of material.
Designated Villains: Calvin's parents, Miss Wormwood, Susie, Rosalyn and Moe all fall into this trope at different times, since they only react to Calvin's own shenanigans (except for Moe, who will torment Calvin whether provoked or not). Even Bill Watterson himself feels sympathy for Miss Wormwood, whose staid, boring teaching style is just about the least effective way to get through to a kid like Calvin. As for Moe, Watterson writes the following in the Tenth Anniversary Book: "Moe is every jerk I've ever known. He's big, dumb, ugly, and cruel. I remember school being full of idiots like Moe. I think they spawn on damp locker room floors."
In one strip, Calvin pretends he's flying a fighter plane and ends up blowing up his school. Watterson apparently got a few angry letters when it was first published, but defended it by saying that any kid Calvin's age has probably dreamed about blowing up their school at least once. Now that school shootings have shown themselves to be all too real, there's little chance it would be published at all today.
In another strip, Calvin draws a squadron of B-1's nuking New York in class. Due to 9/11, there's a slim chance a strip like that would get the green light.
Somewhat minor example — one story arc has Calvin using his "Stupendous Man" costume and persona in an attempt to ace a history test ( he flunks). His mom, as punishment, takes away his costume. While she's done this before, given that this story arc is Stupendous Man's last appearance in the comics, it makes you wonder if said costume wasn't confiscated permanently.
Gateway Series: If you can find any comic after the 70s besides Peanuts or Garfield that has left more of a mark and gotten more people into newspaper comics, chances are it will be Calvin And Hobbes.
Germans Love David Hasselhoff: The strip quickly became popular in the UK and is still reprinted in some newspapers there to this day. The collections are also still sold in bookshops. Go in any branch of Waterstones' and you'll still find people buying them.
Not only that, but when the 25th anniversary of the strip came round (in 2010), BBC Radio 4 made a documentary celebrating the strip, hosted by ''Never Mind The Buzzcocks"' Phill Jupitus. In said documentary, people were interviewed buying the books in Waterstones and other bookshops, showing how beloved it is in the country.
Genius Bonus: From one strip where Calvin asks his mom if hamburgers are made from people in Hamburg. While that is obviously (and hopefully) not the case, hamburgers DID get their name from Hamburg, Germany.
Lead characters named after John Calvin and Thomas Hobbes also fits into this trope. Same with Miss Wormwood.
In one strip, Hobbes claims "If you don't get a goodnight kiss, you get Kafka dreams." The rest of the strip is about the duo fighting off an enormous bedbug.
What's more, a throwaway gag from one New Year's strip has Hobbes asking Calvin if his parents celebrate the new year. Calvin notes that their idea of a party is "mixing regular coffee in with the decaf." Then there's "New Year, New Disasters", which has Calvin invited to a New Year's party, while Calvin's parents drown their sorrows in cider.
This strip following the controversy surrounding James Frey's A Million Little Pieces.
May 12th, 1991: Calvin, disillusioned that the same generation that protested "The Man" has become "The Man" themselves, starts listening to easy-listen muzak to start his own protest. Did he just invent Vaporwave?
Jerkass Woobie: Let's not sugar coat it. If Calvin weren't a lazy, self-centered and a mild example of Small Name, Big Ego, he'd be a very sympathetic character. He gets beaten up constantly by Moe, Susie, and Hobbes, is a Butt Monkey overall, and is ignored by his parents. It's made very clear that Hobbes is his only friend. It's really easy to see why he's prone to Jerkass moments. It makes the tender moments he and Hobbes have together all the more touching.
Misaimed Fandom: Fans often debate whether Hobbes is "real" or "fake" (see the Headscratchers tab for examples). Watterson carefully avoided making such a distinction and held that it defied the point of the strip.
The "Nauseous Nocturne", a poem about Calvin being menaced by monsters at night. And is eaten alive. With illustrations of his bones.
In one Sunday strip, Hobbes disguises himself as a Bedsheet Ghost to scare the crap out of Calvin. You'd think that would make the pic inherently silly, but out of context, the pic in question (which is the page image for Bedsheet Ghost) is so well inked and moodily colored, that it really convincingly sells why Calvin would be so terrified.
Older Than They Think: Watterson revealed in the 10th anniversary book that Spaceman Spiff is actually the first comic he tried to sell to newspapers, which had its origins in a very silly comic he wrote for a college German class. He quickly realized that Calvin's fantasies gave him the opportunity to actually use some of his ideas for Spiff, and occasionally give himself a break from writing Calvin and Hobbes.
The Scrappy: Moe, an obnoxious and one-dimensional bully whose only purpose is to make Calvin's school life miserable. Calvin's creepy revenge fantasies against Susie and the other kids aren't justified. Against Moe, however...
Toy Ship: Calvin and Susie. It's not really central to the ship — primarily because Calvin's still at the 'girls are icky' stage of childhood — but it is hinted at. A popular bit of Fanon is that Calvin and Susie end up getting married when they're older and having kids of their own.
What Do You Mean, It's for Kids?: Despite being made mainly for kids in its early years, the strip now has just as much of a following with adults. Particularly in the later years, there were a ton of jokes that just wouldn't make sense to kids, and even a couple that implied jokes about sex and drugs.
Despite being capable of great Jerkassery, Calvin can come across as quite sympathetic when he's getting picked on by Moe or when things are going badly for him.
Susie tried to make friends with Calvin before she realized the futility of it, and was genuinely hurt by Calvin cruelly rejecting her time and again. This side of her is shown in a few cases, such as when her feelings are hurt by Calvin insulting her.
Finally, the entire family were Woobies after their house was burgled, particularly how Calvin's father ponders that he always thought he would know what to do in a situation like this when he grew up, but nothing could have prepared him for this.
Before he got Put on a Bus, Uncle Max had this Woobie-worthy exchange:
Calvin's Mom: Didn't you ever have an imaginary friend?
Uncle Max: Sometimes I think all my friends have been imaginary.
One Polish translation of the strip renamed it Kelvin & Celsjusz* Kelvin and Celsius , while the Finnish one renamed it Lassi ja Leevi after Lars Levi Lęstadius. The Norwegian name of the strip is Tommy og Tigern* Tommy and the Tiger.
In one strip, Calvin complains about "the lack of sex education" because the English language doesn't have grammatical genders. When it was translated into Norwegian, which has grammatical genders, Calvin complained about grammatical genders being politically incorrect.