Obfuscating Stupidity: Kyon constantly denies knowing or understanding things that the events or narration show that he does, as a way of avoiding conversation with others; most notably Koizumi, but also quite a bit with Taniguchi.
Itsuki initially believes that Mikuru may be using this to win Kyon over to her side.
Ostensibly the goal of the SOS Brigade, though they very rarely get around to it. Though, to be fair, the SOS-Dan's objective has already been fulfilled: "To find aliens, time travelers, sliders and espers and have fun with them", right...?
They haven't found a slider yet. Unless Kyon counts after "Disappearance". Probably not, though. It was technically the same universe.
In the eleventh novel, Yasumi fulfills the role of slider, joining the SOS Brigade in one timeline, and popping in to confuse Kyon in the other.
Odd Friendship: Kyon (laid-back and skeptical) and Haruhi (borderline sociopath with a huge belief in the supernatural). Really, everyone in the S.O.S. Brigade to some extent. Mikuru and Koizumi are in rival organizations, Yuki was not supposed to develop human emotions, and Kyon was not supposed to be there at all. Yet they all become friends.
In Disappearance, Kyon's reaction to the revival of Ryoko. Understandable when your last interaction with a person was her trying to stab you to death. This reaction turns out to be wholly justified, too.
Towards the end of Melancholy Mikuru accidentally stumbles across the folder where Kyon stashed her sexy maid pictures. The dub put it best:
Kyon: I'm screwed!
His general reaction to, well, the disappearance of Haruhi is pretty frentic as well, especially since his initial thoughts center around the idea that she somehow unmade herself (and just how profoundly fucked the universe might be in this case, given what he knows).
Realizing the true nature of the paradox, what caused it, and exactly what his decision could mean for Yuki. (And everyone else, but Yuki above all.)
In Bamboo Leaf Rhapsody, when young Haruhi says, "North High, huh," Kyon's eyes immediately show that he's fully aware of how monumental that moment is, and what it means for his future.
Kyon is similarly disturbed in the preview for Surprise when Yuki's text messages reassuring him that there is nothing to worry about suddenly degenerate into unintelligible gibberish, and he becomes horribly aware of just how much strain Yuki is being put under. And then Asakura comes back.
Itsuki's face in the novels when he realises his screen-time in the movie he doesn't want to be in has been increased due to his questioning of the lack of characters. Considering his typical Stepford Smiler expression, the fact that his smile becomes visibly strained in the anime can probably still be considered an "oh crap" face.
In Someday in the Rain Haruhi is bending over a sleeping Kyon. She has her best Oh, Crap face of the series when he wakes up and she even holds it for about 10 seconds.
In The Sigh of Haruhi Suzumiya, one of the climactic moments happens when Kyon almost slaps Haruhi in anger after she declared Mikuru "property." Kyon is too upset to notice in the novels, but Itsuki stops smiling and is visibly alarmed (which, for him, may as well be as frightened as he can express) at this point. Itsuki later admits that he was afraid that Haruhi would have had a breakdown and rewriten reality right then and there if Kyon hadn't been stopped.
And earlier in Sigh, when one of Mikuru Beams slashes the light reflector right above Itsuki's head. You know shit's gone completely out of control when Koizumi stops smiling.
Ominous Latin Chanting: Bilingual Bonus, to boot; the music is part of the first movement of Mahler's 8th Symphony, and the lyrics are taken from the Latin hymn, "Veni, Creator Spiritus", which talks about the creator of the world.
One Head Taller: This becomes extremely obvious in the gender-bent fan version: when you switch the genders, the heights are also accommodated.
One Steve Limit: Haruhi is a very common name in Japan, but in the Disappearance movie, on December 18, no one at Kyon's classroom seems to know a single Haruhi. The novel explains that all of Haruhi's classmates from her junior high were out sick that day.
Only One Name: We never get to know Tsuruya's complete name; it's never even made clear if Tsuruya is her first or second name. People who don't hang around with her call her "Tsuruya-san" and Itsuki refers to "The Tsuruya Family", so it may be her second name, but Haruhi calls her "Tsuru-chan" so it could very well be her first name. The fact that the name Tsuruya can serve as both doesn't help.
Orange/Blue Contrast: Somewhat. The covers of volumes 10 and 11 of the light novels are orange and blue respectively, and they're getting a simultaneous release. Bonus points because it further shows how Haruhi and Sasaki are on opposite ends of...whatever.
Ordinary High-School Student: Kyon actually is confirmed completely 100% ordinary. Through background checks. For now at least. Considering that this is the Haruhi verse, it's quite possible that this will change. The fact that sliders are so far unaccounted for has caused many fans to believe that Kyon may eventually become a slider.
Or Was It a Dream?: What Kyon is asking himself after the climax of Melancholy, until it becomes obvious.
Our Souls Are Different: Data entities like the cave cricket the computer club president ran afoul of can exist even after their physical medium has been destroyed. When Yuki is explaining this, she lets slip that this is true of data in general, not really anything unique to these entities. Kyon realizes the implications of that statement, and asks if human souls exist. Yuki's response is...interesting.
Nagato, she— "..." She was silent, she was blank, and yet I felt that there was some kind of a look to her. And so long as my perception wasn't indicating "zero"— "..." It was like she was trying to avoid smiling at her own joke. "That is classified."
In Disappearance, when Yuki left it to Kyon to choose between the old and new worlds
Kyon does something like this on a daily basis in the series, but without anyone willingly empowering him.
Overly Long Gag: "Endless Eight", with a full eight episodes. Based on one single 30-page chapter. With each episode about 24 minutes long, the gag ran for three hours and twelve minutes. It has notbeen received well. The Arc Number is visually cued in episode 6: Kyon endlessly repeatedly scrawls an '8' into Haruhi's checklist, and from the camera angle it appears to be the sign of 'infinity'. Yes, eight whole episodes were committed to this symbolism. Let's put this in perspective. While it only takes three hours and twelve minutes to watch every episode, this is not what was was Overly Long about it. Many fans watched these episodes as they came out over the course of a few months. Yuki Nagato was an effective woobie because after about 4 episodes the viewers began to get more and more frustrated and felt like they themselves were stuck in the endless recursion of time with the characters. It didn't help that each episode teased at breaking the cycle at the very end of each episode, only to have Kyon not know what to do/chicken out.
Pac Man Fever: Possibly justified, as it was a game built by a bunch of talented amateurs.
Pals with Jesus: Kyon. To the point that anyone who wants to affect Haruhi in any way goes through him first (sometimes with a knife), to his irritation. It's combined with Kid with the Leash for Yuki, who listens to Kyon and Kyon only.
Haruhi: Okay, Yuki, wreck her with your magic! Yuki:...[looks over at Kyon] Kyon:[narrating] No. No. No. I shouldn't even have to tell you that.
The layout of the 2009 episodes plays around with this by reflecting their content: the new episodes came three years after the first run, playing on the interval of time travel in "Bamboo Leaf Rhapsody"; "Endless Eight" had eight iterations; and The Sigh of Haruhi Suzumiya, about the SOS Brigade's creation of a movie, was treated like a single long movie-like episode and simply cut whenever each episode's time limit was reached (even in the middle of conversations). It had also become a minor meme to state that "Disappearance disappeared" or some variation of it, but it's now The Movie. And it was released on DVD and Blue-Ray on December 18, a majorly significant date in the story.
Despite the majority of the tenth novel taking place in April, Kyon travels a month in the future in the ending.
Itsuki. Not only effective as The Philosopher but nearly as difficult to follow as his ancient Greek forerunners. Just trying to make sense of what he's saying is a mental workout, for the audience as well as Kyon.
Shamisen deserves an honorable mention. Although he only has one speech, he's a good enough philosopher that upon being introduced he manages to sidetrack the brigade members into a debate over the nature of conversation and away from the fact that, you know, he's a talking cat.
Sasaki exemplifies this trope, so much that even the aforementioned Itsuki is impressed. You have to admire someone who can come up with a clever and confusing speech about light and quantum mechanics on the drop of the hat while talking about schoolwork.
Haruhi will talk about her philosophy at various points only when alone with Kyon though. Like when she explains how she became the way she is in Melancholy or when tutoring Kyon in Suprise. She also knew the origin of Rousseau's name.
Precision F-Strike: In the anime: "Then I'll tell everyone at school that all you geeks ganged up on her and fucked her!" Of course, the line in the novel is the relatively innocuous "gang-raped". In the Disappearance novel, Kyon swears once at the very end (apparently for the first time in the series). By the Astonishment novel, he's less restrained.
Press-Ganged: Pretty much everyone in the SOS Brigade can attest that they were bodily forced- er, recruited using this method.
Prima Donna Director: Haruhi throws some epic tantrums during the making of The Adventures of Mikuru and displays some of her worst behaviour for the entire series.
Prolonged Prologue: The novels often have extremely long prologues, or at least chapters titled so. Kyon lampshades the very long prologue of Disappearance, but the prologue in Intrigues is nearly twice as long as that, and the prologue in Dissociation is in turn considerably longer than Intrigues. Kyon does have a point though, despite their length there really isn't any other name for them other than "prologue" as they don't quite fit into the story proper.
Puberty Superpower: Haruhi and Koizumi both gain their powers at age 12 (Koizumi because of Haruhi).
Public Domain Soundtrack: Classical music is used very effectively throughout the series (see the trope's page for details).
Asakura (Red) and Yuki (Blue). Actually subverted, as their inner workings are exactly flipped.
The same dynamic applies to Haruhi and Kyon (Haruhi's theme color is red, though Kyon is yellow since Yuki means blue is taken), but it takes a somewhat closer reading to see who, when it comes down to it, is actually inclined to be a hothead and who's prone to, well, melancholy.
Red Pill, Blue Pill: Kyon is given the choice to either remain in the new world where espers, aliens, and so forth don't exist or return the world to its former crazy, troublesome self.
Rescue Romance : Well, friendship at least. The start of the Yuki x Kyon Ship Tease is her saving him from Asakura. Interestingly, she's portrayed as slighly creepy prior to this incident. After this, Kyon warms up to her a bit, and she is portrayed as much less creepy.
Restraining Bolt: Yuki places one of these upon herself after the events of Disappearance as a precaution, disabling her ability to time travel via synchonization. This also has a unique subversion — losing her knowledge of what the future holds gives Yuki "freedom beyond what I had imagined", allowing her to exercise free will for the first time... And as a result, she spontaneously offers to make dinner for Kyon and Mikuru. D'aww.
Rhetorical Request Blunder: Throughout the Haruhi series, Kyon continually wishes that he were living a normal life. In the fourth book Yuki provides just that.
Ripple-Effect-Proof Memory: Averted and played straight. Once in "Endless Eight" and once in Disappearance. The times it is played straight are explained. Yuki in "Endless Eight", because her information is the time frame and Kyon in Disappearance, because Yuki precisely made it so he'd remember.
Robe and Wizard Hat: Yuki wore this for her fortune-telling, the student film, and impromptu guitar replacement. "The Wizard of Rock" indeed.
Scenery Censor: It's a Running Gag to have characters and objects blocking the view of Haruhi forcibly stripping a flustered Mikuru while commenting explicitly on her body. It was played most obviously and repeatedly in "Someday in the Rain", with recurring shots of Yuki discretely turning to gaze into the bookshelf while Itsuki courteously leaves the room.
School Uniforms are the New Black: Yuki Nagato will wear her school uniform even when the rest of her friends change into their casual clothes. Kyon suggests that maybe she just likes her school uniform because she exhibited similar behavior with her fortune telling/witch costume.
Secret Keeper: For three opposing factions, all whom seem to get along pretty well for opposing factions, although it is mentioned that certain parties within each group don't get along as well as the three close to Kyon. Until he actually tells Haruhi about it. Luckily (?), she's an Agent Scully.
Kyon's non-comprehension of Haruhi's feelings for him is acceptable in the anime, as the series is short and romance is not a gigantic focus, but it's getting downright ridiculous in the novels. It's even got Itsuki openly exasperated. Bear in mind though that in regards to his feelings for Haruhi, Kyon's an Unreliable Narrator. The issue is less any stupidity on his part and more of a refusal to understand. But on the other hand, there are occasions where Kyon's thoughts clearly betray that he knows that if Haruhi gets jealous over him she might end the world. Happens in "Live Alive" and Sigh.
Given that twice in the anime ('End of the World' and Endless Eight) solutions cause Kyon to directly interact with Haruhi on a personal basis, it might be less of 'obliviousness' and more 'refusing to see it'.
Subverted: Although Mikuru is Haruhi and the others' senior, she still gets used like a dishrag by Haruhi.
Yasumi calls Kyon "sempai".
Sequel Hook: In the end of Surprise, Kyon travels a month into the future, and because there already is another Kyon in that future, he must return to mend the timeline. It also will serve for us to find out what the hell happened.
Part of the same time slip shenanigans, before Kyon travels one month into the future, into Haruhi's room no less, he actually gets dumped into an even further future to a place that appears to be a college campus. To his surprise, there is an older Haruhi staring down at him in surprise and confusion as to why he's wearing his old uniform. The kicker? He also catches a brief glimpse of his future self running up just before he fades away with Haruhi smiling at him. The implication? Kyon and Haruhi are still together even in college. It's pretty good payoff when Haruhi had been helping Kyon to study throughout volumes 9-11. Even better yet, Kyon decides he wants to work toward making that future happen so he can see that Haruhi again. That's one hell of a sequel hook.
Series Continuity Error: In the movie, Haruhi says she had sworn off alcohol. However, the kids were never drunk in the anime version of Lone Island Syndrome. The dub sidesteps this, as mentioned above under Bowdlerize.
Sexy Discretion Shot: More like a nudity discretion shot. In "Someday In The Rain," whenever Haruhi changes Mikuru's outfit, the viewer is treated to what could only be described as sounds of rape, a shot of Nagato's face as she's picking out a book, and Itsuki standing outside the room saying something completely unrelated. Nagato is apparently Genre Savvy and aware of the viewer and the camera placement during these scenes. At one point after switching out her books during one such occasion, she makes a deliberate glance at the bookshelf, and presumably, the viewer, as if she knows what we're all thinking.
Shadow Archetype: Kyon and Haruhi to each other. Kyon is the rational Agent Scully that Haruhi learnt to suppress for the sake of fun. Haruhi is the irrational Daydream Believer that Kyon learnt to suppress for the sake of order (and lack of disappointment) in his life. To a lesser extent, Itsuki and Taniguchi could be considered Kyon's shadows, contantly bringing up things that Kyon would prefer not to think about.
Kyon kissing the princess awake is naturally, yet frustratingly, wiped out with All Just a Dream.
Intensifying Ship Tease concluding each episode of the "Endless Eight", until Kyon's momentous epiphany...of Anti-Climax.
In ''Snow Mountain Syndrome" Kyon and Haruhi get into a spirited game of Twister.
In novel 11, Kyon is sent a month into the future. Where does he appear, you ask? On all fours over Haruhi in her bed. And Haruhi doesn't seem very bothered by it. To make it worse: She is the one who sent him there in the first place.
As part of the same time slip, Kyon actually ends up going a few years into the future, appearing in a college campus, where an older Haruhi is waiting to meet him. She's initially confused at him wearing his old uniform, but smiles when Future!Kyon does show up.
Also, the books within a book, when Haruhi forces the SOS Brigade to write short stories for a magazine to save the Literature club from being disbanded due to lack of membership. Through these, we get some interesting looks at the personalities (and possibly even back stories) of the SOS Brigade; especially noteworthy is Yuki's, where it is hinted that Kimidori has known Yuki since she was first "born," and helped her come up with her name.
Sighted Guns Are Low Tech: The hypodermic dart gun that Yuki gives to Kyon in Disappearance in order to inject the corrective program looks distinctly sci-fi-ish (or like a toy); either way, it is missing its sights.
Silent Bob: One single word with a bit of emotion from Nagato says it all.
"Silly Me" Gesture: Kyon's sister's trademark. Future Mikuru also does it in Disappearance.
Single-Target Sexuality: Yuki Nagato may be Kyonsexual. Given that she's a stoicEmotionless Girl who hardly says a word to anybody, it's interesting that she talks with and defers to Kyon on a regular basis. Then there's also that time Nagato recreated reality, including shunting the other three members of the Brigade out of the way. The alternate version of Nagato had a pretty obvious crush on Kyon.
The Singularity: Mechanical technology is a dead end in the Haruhi-verse: both the Aliens and Time Travellers are past it. Mikuru can't operate anything more complicated than a flashlight because what she's familiar with isn't remotely similar; when asked about the future, she can't reveal anything, but her non-answers imply that mankind doesn't even need to use boats anymore. This makes Yuki's love of Science Fiction novels and games an interesting quirk.
Sliding Scale of Realistic Versus Fantastic: the series has three discernible layers with regards to this scale: a Mundane layer (Kyon, school life and the club's for-fun activities), an Unusual/Fantastic layer (the aliens, time travelers and espers, whose powers are bound by rules they don't create), and a Surreal layer (Haruhi, whose power is implied not to be bound by the rules that the others' are).
Slipstream: With all the post-modernism, genre-blending, and the layered scale above, this is about as close to a genre as this series is likely to get.
Space Whale Aesop : Endless Eight Haruhi created a Ground Hog Day Loop that went around 15,000+ times and drove Yuki(who remembered all of it, rather than having her memory reset eachtime like everyone else) insane enough to cause the Disappearance plot line because....Kyon didn't do his homework. To be fair, her subconscious probably didn't know it would be as bad for Yuki as it was.
Spell My Name with an "S": The usual problem with the extended "o" sound. Kuyou Suo? Kuyou Suou? Kuyo Suo? Kuyoh Suo? For that matter, Ryoko/Ryouko Asakura. Her surname is easy enough, but her given name sparks nerd-fights over the exact way to spell it to reflect pronunciation.
Kyon is John Smith, who met a young Haruhi and influenced her to become who she is today; at one point in the novels, there are four Kyons and three Mikurus existing simultaneously.
When an older Mikuru informs Kyon about her star-shaped mole, only to realize he was the one who told her about it, and he didn't know until she told about it. She's understandably upset at the implications.
Following Future Mikuru's instructions, the two of them plant the basic ideas of time travel in the head of a primary school boy. Present Mikuru recognises him as the future inventor of time travel.
The events of Intrigues. At the end of the novel Kyon sends Mikuru 8 days back into the past to find him and follow his instructions, because at the beginning of the novel he finds the 8-days-later Mikuru that he will send back.
At the end of Disappearance, future Kyon, Yuki, and Mikuru come back to save Kyon's life after he's stabbed by Asakura. Think about that for a minute: If Kyon hadn't survived at that moment, he couldn't have gotten them to come back in time to save his life at that same moment. He lived because he lived.
Starfish Aliens: The Data Overmind and its "inhabitants" are really these, even if the Interfaces all look like high school girls. Also hilariously played with in the Book 10 preview, as the residents of the Canopy Domain are incomprehensible Starfish Aliens to the Data Overmind. Part of the reason Ryoko engaged Kuyo was to try and gain at least a modicum of understanding of the latter. For Kyon's part, he finds Kuyo so unbelievably alien and bizzare that he calls her and her fellows straight-up Eldritch Abominations. Even more hilarious, however, is the suggestion that the Data Overmind (and the Canopy Domain, for that matter) ultimately view humans as a kind of Starfish Alien. Just consider the fact that specific "Humanoid Interfaces" needed to be constructed to even attempt to communicate with mankind. It also explains a lot of their oddities; for example, Yuki's furnishings are very simple because she literally does not understand the need for decoration or comfort (at least at first), those being relatively pointless (as we know them) to her in her "natural" state.
Start My Own: Haruhi's motivation for starting the SOS Brigade. No bonus points for guessing who gave her the idea. Guessing that the same person also inspired the odd name? You might be a genius.
Stating the Simple Solution: During the filming of the student movie, an in-universe Plot Hole is pointed out: If Yuki has the power to control minds, why doesn't she just mind control Itsuki instead of doing the whole roundabout method of recruiting him? Unfortunately, this is brought up while the camera is running, by the cat. Kyon yells from offscreen for him to shut up, or he's not getting any dinner.
Itsuki, always cheerful and smiling even if the world is in serious danger. Kyon is not amused. Itsuki is always smiling, anyway. There are many hints, even in the anime, that he is jealous of Kyon a bit.
Ryoko Asakura. Big Time. Her cheerful personality is, at best a facade over total lack of emotion and lack of understanding of human concepts.
Still The Leader: Downplayed most of the time. There's no chance of Haruhi ever losing her role as the Brigade's official leader, but whenever Kyon starts making plans or instructing the other Brigade members without her input, she still feels obligated to remind him that she's the leader and it's her job to give the orders (even though she usually just ends up going along with his ideas anyway). Kyon attributes this to her competitiveness.
The Stinger: After the Disappearance movie. Yuki is shown reading by herself at the public library, but stops for a moment to watch a boy help a girl make a library card. Yuki then looks toward the camera and does that adorable thing where she holds her book in front of her face with only her eyes peeking out over it. Who said Yuki needed emotions to be moe?
Stockholm Syndrome: Adult Mikuru looks back on the days in the SOS Brigade fondly. Whether it's really stockholm syndrome, or Nostalgia Filter, or she started to simply enjoy it for it's own sake is uncertain though.
Kyon and Haruhi provide a number of subtle examples of this. Arguably the reason why Haruhi "chooses" Kyon.
In the very beginning of the chronological first episode, Kyon specifically mentioned that in the past he hoped that there are "aliens, time travellers, and espers".
Kyon seems to actually understand the logic of pre-SOS Brigade Haruhi's cyclical hairdos, and can follow her explanation of which color belongs to which day. The only part they disagree on is the numbers assigned to the days: She says Monday is 0, making Sunday a 6, whereas he thinks Monday ought to be a 1, presumably making Sunday 0 or 7.
In "Bamboo Leaf Rhapsody" there's a couple of superficially apparent false examples of this: Kyon tells Haruhi to go get the line marker before she explains what they're going to do (which visibly surprises her in the anime), and he also manages to guess the symbols are a message to Orihime and Hikoboshi without her explaining it. He has the advantage of, well, knowing high-school Haruhi, but her middle-school version seems surprised at John Smith's ability to understand what she's thinking. On the other hand, Kyon imagines the message scene when first told about it back in Melancholy. He actually got some of the details right, like her stealing the materials ahead of time.
In "Someday in the Rain" and Disappearance, both Kyon and Haruhi, upon being woken up by the other, think that the other one must have been drawing on their face.
In the 8th book, both Koizumi and a random passerby come to the conclusion that cats and dogs must be avoiding a certain area because there is a hibernating bear somewhere. In the middle of the town. In the same book, both Haruhi and Sakanaka's father use the nickname "J.J." for a dog called Rousseau. Maybe they had the same philosopher in mind.
In Sigh, Kyon accurately guesses why Haruhi wanted to make a movie.
101 Hamsters, but perhaps this is an artifact of her powers at work.
Stylistic Suck: The student film in "Episode 00". One of the few justified examples, as it's a student film, trying to look like a Toku show. Oddly enough, the effort required to achieve this look in animation makes it perhaps the most technically sophisticated episode.
Subordinate Excuse : Haruhi uses this a lot to help out Kyon. It's her reason for staying in the hospital in Disappearance and she tutors him later in the novels. Interestingly, she can take care Yuki because she's worried about her.
Subverted Trope: In Disappearance we are initially led to believe that, since he's in an apparently alternate universe, Kyon is technically our much-awaited slider. He's proven to not be one in short order when we find out that he didn't go to an alternate universe; Yuki just changed everyone's memories in the current one.
Super-Deformed: Haruhi-chan and Churuya-san, though apart from these self-parodies, it consistently averts the trope.
Super Power Lottery: Yuki, and how! Haruhi's got a winning ticket, but we'll see if she ever cashes it in.
Super Reflexes: Nagato can react fast enough to block lasers. That would require her to move at faster than light speeds. It's never made clear if the lasers gave some sort of sign that they were about to go off, giving her time to react, or if she can just move at faster than light speeds. Asakura's fight in Surprise implies that she stopped time. The Hyperion Cantos reference would also support this (it's one character's Signature Move).
Supporting Protagonist: Haruhi is usually the focus of the story (and leader of the brigade), but Kyon is always the main character.
In "Live Alive," after wolfing down his lunch at top speed, Kyon takes a walk just to settle his stomach and certainly not to look for Haruhi. Seriously. There was no other reason. Don't read too much into it.
Also, when filming "The Adventures of Mikuru Asahina," there was no extra footage of her being undressed by Haruhi. None. At all. So don't bother asking for it.