He might have meant well, but John Winchester was a neglectful bastard who messed up his sons incredibly badly. Even Dean, who began the series utterly devoted to John, eventually admitted that he was an "obsessed bastard."
Max Miller's father and uncle beat him up daily while his stepmother stood by and said nothing.
Accidental Kiss: Bobby excitedly lays one on Sheriff Mills after she discovers that Borax can hurt Leviathans.
Adorkable: The titular character in "The Girl with the Dungeons and Dragons Tattoo" is very plainly this, almost excessively so.
Also, by his characterization Sam Winchester is this. As is Castiel and Kevin Tran, the A Prophet of God who can read his "Word" etched onto ancient tablets by the Archangel Metatron
Acting Unnatural: Parodied. Dean and Sam are transported to an alternate universe, where they are mistaken for the actors Jensen Ackles and Jared Padalecki, who are currently filming this very episode of Supernatural. They decide to play along, failing miserably in the task of portraying their respective characters. Lampshaded by Robert Singer, who remarks that they apparently lost any shred of talent.
Adult Fear: Episodes like "The Kids are Alright," "Home," and others deal with things that would scare the hell out of any parent with a young child.
Aerith and Bob: Frequently. Probably best exemplified by the fact that for the first two seasons, their primary enemy was the demon Azazel, and his Dragon, the demon Meg.
Although, Meg is actually the name of the possessed girl, the actual demon's name never being mentioned. The demon comments once that she thinks it's hilarious that the Winchesters still call her "Meg".
Affably Evil: Casey in "Sin City," the old Pagan God couple in "A Very Supernatural Christmas," Lucifer, Patrick (the card-playing he-witch in "The Curious Case of Dean Winchester") and Crowley. Osiris often comes across as this in "Defending Your Life". Though some of these are just Faux Affably Evil
All Therapists Are Muggles: In the episode "Sam, Interrupted", Sam and Dean do go to a therapist and try to explain their problems. Shortly after they start into why they have these issues they get committed. (Fortunately, that was the plan.)
All Your Powers Combined: The only way to kill a Leviathan is to have the bone of a righteous mortal washed in the blood of a fallen angel, the king of fallen humanity, and a father of the fallen beasts on hand. That is basically the four main races of the series (a nun for humanity, Castiel for the angels, Crowley for the demons and the Alpha Vampire for the beasts) required to put down a leviathan.
Ambiguous Disorder: The angel Castiel has a lot of vaguely Aspergers-like traits (Literalmindedness , limited interpersonal skills and No Sense of Humor) and schizoidal tendencies which he attributes to not having spent much time on Earth, even though none of the other angels (including a number who have spent less time on earth) have any of his problems. Before the civil war, he seems to have been fairly well-liked and to have had a good relationship with his angelic siblings, so his quirkiness probably hasn't caused him any real problems.
Sam and Dean bury Doc Benton (who's immortal) alive, chained up in a refrigerator. Another thing to consider: although he can't die, his body parts wear out, so eventually he'll rot away into a sentient and forever conscious pile of dirt.
The episode "The Rapture", in a slight subversion, has the good guys bestow this kind of fate upon another good person. Jimmy, the vessel for angel Castiel, begs Castiel to possess him to save his daughter from having a similar fate. It's essentially the fate for every human possessed by an angel or demon. Even the "good guy" angels like Castiel, Anna and Gabriel have been pulling this stunt for countless millennia.
Also intentionally given by the good guys to H.H. Holmes, the USA's first recognized serial killer. They left the ghost underground, encircled by rock salt. And barricaded the place. And for good measure, sealed the entrance up with concrete in case of earthquakes. That ghost is NOT going anywhere anytime soon.
In the fifth season finale, Sam actually volunteers to trap Satan by allowing himself to be possessed by Satan and then jumping into an inescapable cage at the bottom of Hell. Because being locked up for all eternity with a very pissed-off fallen angel who has nothing to do but take out his frustration on Sam was the only way they could think of to prevent a global apocalypse. Downplayed because his body gets set free by Castiel not long after, and his soul a year later by Death.
Played for very dark comedy with a teddy bear brought to life by a child's wish, which finds it can't even commit suicide.
Sam and Dean use this to beat the high demon Abaddon in "As Time Goes By". First they shoot her in the head with a bullet engraved with a demon trap, permanently locking her in her meatsuit, which she can barely move. Then (offscreen) they cut her up into little pieces, and to boot it off, bury them in cement, encasing her for at least a few thousand years. As Dean put it, she'll wish they had killed her.
Animal Wrongs Group: Surprisingly, the Devil and his followers. He actually wants to turn Earth into a massive nature preserve...but he also wants to murder most of humanity and zombify most of the survivors.
Many characters believe that this includes demons, who were all humans at some point. Lucifer never confirms or denies this.
Angels, Devils and Squid: The mythology in the series has angels from Heaven, demons from Hell, and Leviathans from Purgatory (which Lovecraft himself attempted to access with a portal). The Angels are hardly paragons of goodness, but the Leviathans are predictably the most evil of all of them. Then there's The Fair Folk, who come from another dimension and seem to be in a different category of supernatural beings.
Anna spent some time in mental institutions as a schizophrenic patient. She fell to become human, was born as a baby and grew up, then regained her own grace.
Archangel Gabriel, who had been hiding as The Trickster since seasons prior. He has been hiding on Earth for millenia and done such a good job of it that other magical beings and even non-Christian gods do not realize that he is an angel and not one of them.
The season 5 finale: Chuck finishes writing his story and vanishes with a knowing smile on his face. Debate is raging in the fandom about whether this means the writer was literally God.
Arbitrary Skepticism: Despite making a career out of hunting supernatural menaces and retaining enough experience and Genre Savvy to fill an aircraft carrier, Sam and Dean Winchester almost inevitably have an argument over whether or not the Monster of the Week could be the real thing or not. Most of this is justified, because presumably the brothers get a lot of dud cases where it's nothing supernatural at all. We never see those cases because an episode consisting of Sam and Dean rolling into town, poking around for a while, concluding "Oh, some guy just got spooked by a barking dog," and rolling out again would be really boring. It's therefore always a legitimate question whether there's actually anything weird going on. Another arbitrary element of this is that the role of the hard-line skeptic switches every time between Sam and Dean.
One memorable scene has Dean explaining to Sam why he doesn't believe in angels (their mother said that angels were watching over them, but she was murdered by a demon), despite hunting demons straight out of Hell on a regular basis. When Sam points out that there's more folklore on angels than any other creature they've fought, Dean says that there's a lot of folklore on unicorns as well. Sam's response? "Wait, there's no such thing as unicorns?" In this same scene, Dean says that there's no God. This is an odd belief given that in this series the name of God and holy water are harmful to demons, and Christian exorcism rituals are effective. (According to the series creator, he just sees the rituals as another example of the hoodoo they regularly run across.) By the end of the episode, Dean is less certain that no higher power is at work. Worse, his atheism has been shaken by the events of the episode despite the fact that the "angel" in that episode turned out NOT to be an angel.
The episode "A Very Supernatural Christmas" featured a series of Christmas-related disappearances (including somebody getting dragged up the chimney). The brothers start to wonder if the monster is some sort of "Anti Claus". They end up doing some research on the concept, investigate Santa's village and try to apprehend the guy playing Father Christmas (who matches the profile of the Anti Claus, but turns out to just be a drunk). After that failure, they consult Bobby who tells them there is no such thing and that Sam and Dean are idiots.
Then comes another episode where all sort of weird things are happening in a single university campus. The only one that throws Bobby is an alien abduction. However, he doesn't act like it's impossible, he just says that even if aliens do exist, he's never come across any evidence of them.
"Clap Your Hands if You Believe" revolves around supposed alien abductions. Dean eventually begins to talk about how they have to "change their entire worldview" after one such abduction. It's actually a leprechaun, posing as an alien expert, and working with the rest of The Fair Folk, who fakes the "abductions" as part of a Deal with the Devil he has with various people.
Despite there being hundreds of years of lore and mythology relating to dragons that pre-dates their inclusion in fantasy fiction and video games, both Sam and Dean believe that they can not exist because they only exist in fiction and video games.
Since season one, the most consistent mantra has been that "everything's real but Sasquatch". It's actually exactly that. By season 4, angels and God are confirmed. Aliens have been confirmed by angels and above stating there's other planets and life forms they could be dealing with. Still no sight of Sasquatch.
Sam in Season 5, in response to his behavior in Season 4.
Castiel in the seventh season episode "The Born-Again Identity" when he tries to fix what he has broken in Sam's head by absorping Sam's crazy into himself.
At The Crossroads: The show takes the ancient association of crossroads with witchcraft and communion with the dead and the Robert Johnson Deal with the Devil myth and makes crossroads the preferred locale for demon deals. There is an entire cabal of demons (Referred to as Crossroads Demons) who can be summoned at a crossroads and specialize in making deals with humans in exchange for their souls.
Author Avatar: The prophet Chuck writes his books under the name of Carver Edlund. Two of the show's writers are called Jeremy Carver and Ben Edlund.
Author Appeal: Sera Gamble, one of the lead writers and executive producers on the show, is in fact a successful, award-winning writer of erotic fiction. Although she was not a writer on the show from the outset, Jared Padalecki has noted at conventions that she does seem to enjoy having Sam tortured. A lot.
Autocannibalism: Leviathans who fail are forced to eat themselves, a punishment called "bibbing" since all that's left in the end is a bloody bib.
Awesome But Practical: Holy water. It hurts demons, but all it does to their vessel is get it wet. And if you need more, all you need to do is bless any body of water with a crucifix pendant.
Back from the Dead: Multiple characters return from the dead, sometimes repeatedly. Sam, Dean, Castiel and Bobby are the characters who return to life and the continue living (Although sometimes they die again later on).
Castiel probably holds the record, having died and come back an average of once a season since his introduction.
Two of those have died so often that the show had to invent an extra afterlife to keep them from getting bored so often.
Bad Black Barf: Black fluid issuing from bodily orifices is usually ectoplasm and is one sign of ghost possession. Black smoke pouring out of the mouth is a sign of the end of a demonic possession.
Bad Dreams: The main characters get hit by these a few times.
In season four, Dean spends many nights tossing over his nightmares of hell. In season seven, Dean is once again having nightmares, this time about Castiel's death and Sam's hallucinations. Well, mostly about killing Sam's monster friend and keeping it a secret.
Sam had nightmares throughout Season 1. While some were visions, the ones where he watched his girlfriend die over and over again still affected him like this. In season seven, his hallucinations of Lucifer began as nightmares.
In one episode, Bobby's nightmares are used against him by a Monster of the Week, as are Dean's.
Bavarian Fire Drill: In order to find clues about the Monster of the Week, the boys regularly pose as police, FBI, priests, Forestry Service rangers, Homeland Security agents, Center for Disease Control officers, Health Department inspectors, state police troopers - they even pulled out badges to convince a little girl that they were teddy bear doctors.
Garth is the master of this tactic, despite his slight frame and nerdy looks. He's successfully disguised himself as an active duty member of the military and a Texas Ranger, among other things. Not bad for guy who was originally a dentist.
Being Good Sucks: Sam and Dean's job as hunters is dangerous, completely unremunerative and, aside from individual thanks from the people they save, the good they do is largely overlooked. The law is after them for a good portion of the series, both their parents and the great majority of their friends and allies have died in the fight, Dean's been sent to Hell and back for his efforts, Sam goes to hell, too, and when body is pulled out but not his soul, he spends a year and a half being a soulless Jerk Ass and is now haunted by hallucinations relating to his time in hell, and all without a roof over their heads. It is a wonder these guys can even get out of bed in the morning.
Being Tortured Makes You Evil: Ruby states that demons used to be humans, before their humanity was tortured out of them in hell. Dean himself gets tortured enough in Hell so that he finally breaks and starts torturing others and enjoying it because it isn't him.
It's also implied that Anna's Face Heel Turn is a result of her being tortured in Heaven.
Do not call Sam Winchester a freak. He will kick your ass.
DO NOT threaten Sam in front of Dean.
Do NOT insult Eve (the mother of monsters) in front of her children, especially the Alpha Vampire.
Beware the Nice Ones: Sam Winchester - he's always got a kind word for someone shell-shocked from a brush with the supernatural, prefers to do research rather than pick locks and break faces, and will most certainly fuck you up if you even think about hurting his older brother.
Castiel may seem amusingly out of touch much of the time, but you really don't want to make him angry. Hell, not even Castiel's True Companions are safe from this. At a perceived betrayal, Cas beats Dean to within an inch of his life. Cas going off the rails is not a pretty sight.
Dean: "Word of advice—don't piss off the nerd angels."
Beyond the Impossible: Normally, unless you are soulmates, you are limited to your own personal sphere of Heaven. Unless your name is Ash however, who managed to discover a means to hack Heaven and walk between the difference spheres, for the express purpose of partying with famous figures from history.
Azazel in Seasons 1 and 2 and Lilith in Seasons 3 and 4. Late in Season 4, it turns out that Lucifer has been the true Big Bad all along and everything in the plot, going back to decades before it, was according to his plan.
In Season 6, after muchcompeting between Crowley, Eve, Raphael and Castiel, the true Big Bad turns out to be Cas, who manipulates everyone else in order to become God.
And in the Season 7 premiere, we learn that Cas accidentally released some ancient beings called Leviathans, which take control of his body and (seemingly) kill him, before mass possessing numerous humans. They (specifically, their leader, Dick) then become the new Big Bad.
In season 8, Crowley once again appears to emerge as the latest Big Bad. And the heretofore unseen Angel Naomi steps up to the plate as well. At the last second however, they both get trumped by Metatron, who succeeds in killing Naomi and manipulating Castiel into a spell that casts the angels out of heaven.
Big Bad Ensemble: The show tended to have more or less consistent Big Bads for its first four seasons, before using this trope in season five:
In season five Lucifer is freed from his Cage, and starts the Apocalypse. He wants to wipe out all humans, as well as the demons, and turn the Earth into his own personal playground, considering it a last testament of God's work. On the other side of this are the forces of Heaven, led by the Archangel Michael. While Michael is the Lesser of Two Evils between the two, he still intends to destroy part of humanity as a "necessary sacrifice" for defeating the forces of Hell and bringing about Paradise on Earth. The Winchesters finds them both despicable, and strive to find another way to beat the devil. In the end, Lucifer and Michael both get trapped in the Cage.
Season six takes it even further, featuring four seperate Big Bads. Early on in the season, to start with, we have Crowley - the new King of Hell - who wants to find Purgatory and take control of its souls, and the Archangel Raphael, who is trying to take control of Heaven and restart the Apocalypse. Then, midway through the season, we meet Eve, the "Mother of All", who wants to overrun the world with her "children". And then, a few episodes before the season finale, we find out that Castiel has been in a tentative alliance with Crowley to find Purgatory so that he can defeat Raphael and prevent his plans from coming to fruition.
Eve is killed about the same time we find out about Castiel and Crowley's alliance, so that knocks her out of the competition. This all comes to a head in the season finale, where Castiel cuts Crowley out of the deal; Crowley retaliates by teaming up with Raphael, only for Castiel to Out Gambit them both. He absorbs the souls of Purgatory, kills Raphael, and sends Crowley running, all before proclaiming himself the new God.
Season eight has the Winchesters fighting both Crowley and the angel Naomi — the latter indirectly most of the season through her Manchurian Agent Castiel — for control of the Word of God tablets. Abaddon gets in on the act near the end of the season as a potential Starscream for Crowley while Naomi has a Heel Realization in the finale, only to be killed by Metatron, who casts a spell to banish all angels from Heaven.
In "On the Head of a Pin," Anna saves Castiel just as he is about to be killed by Uriel.
Castiel pops in to save Sam and Dean in the Season 5 premiere. He plows through two angels and scares Zachariah away.
Big Entrance: Castiel's first scene. All the lights start flickering and bursting, the roof starts rattling, and the barn door breaks open, and Castiel casually strolls in amidst the howling wind and sparks.
Dean: (panicked) Who are you? Castiel: I am the one who gripped you tight and raised you from Perdition.
Sam lets one out at the end of the pilot episode when Jessica dies.
In "All Hell Breaks Loose", Dean also lets out one when he just finally found Sam and seen him get stabbed in the back. Helped by the fact that the viewers are probably feeling the same thing and his look of complete panic and devastation at the sight of his little brother getting knifed.
This is Gordon's reaction in "Fresh Blood" as he's being turned into a vampire.
Played absolutely hilariously when a wishing well turns a girl's teddy bear into a life-sized, sentient being. A very depressed, alcoholic, somewhat perverted, plushy sentient being. Eventually, he (it?) decides to end it all and sticks a shotgun in its mouth, graphically blowing a cloud of fluff across the room. Which doesn't kill it, as apparently cotton batting doesn't double for brains. Despairing, the teddy raises its paws to heaven and implores "WHHHYYYYYYY?!"
Dean reacts this way in "Swan Song" when Sam!Lucifer telekinetically snaps Bobby Singer's neck.
Blessed with Suck: Sam's visions of doom. As one of a group of psychic children, some of whom have powers such as Super Strength, Mind Control, Telekinesis and the ability to electrocute people with a touch, he gets uncontrollable, painful visions of violent deaths. As one of the other psychics put it: "Dude, [that] sucks."
Season 1 Finale: John and the boys have just been in a nasty car accident. We see them in the destroyed car, but don't know if they are alive or dead until the season 2 premiere.
Season 3 Finale: Dean is killed by hellhounds, and his soul is sent to Hell, leaving his future uncertain. Overlaps with Downer Ending.
Season 4 Finale: Castiel is facing off an archangel, said to be one of the most powerful entities in existence, and Sam and Dean are faced with Lucifer rising from his cage.
Season 6 Finale: Castiel gives the boys an ultimatum: bow down and swear their love to him, their new Lord God, or be destroyed.
Season 7 Finale: Castiel and Dean just killed Dick Roman, but are dragged along with his soul into the dimensional realm of Purgatory, where the soul of every monster that ever lived hunt for all eternity. Sam is left completely alone back on Earth, which is now the site of a turf war between the remaining leaderless Leviathans and Crowley's demons. Oh, and Kevin the prophet is now Crowley's prisoner.
Bound and Gagged: Sam for a few minutes in "Bloodlust" and Dean for about half of "Hunted." Sam has visions of being this when he is going through demon blood withdrawl.
Brainwashed: Heaven's preferred methodology for dealing with insubordination.
Break The Gamebreaker: Any time Castiel was killed or sent away by sigil; basically the whole of his depowering in five. In season 7, As soon as Castiel gets his memories and full angelic power back, he becomes insane since he takes Lucifer into his mind. When he recovers from *that*, he's a cloud-cuckoo-lander who would rather watch insects than fight...especially since he's still guilt-ridden from giving the Leviathans a free ride in the first place. The Same could be said of the Colt, at first it had only four bullets left, but could kill anyone, even those protected from typical means of death. They used all the bullets conservatively and only missed once. In Season 3 it gets unlimited ammo, making it a gamebreaker, so it is stolen by Bella after a few episodes, and not seen again until Season Five. Where Lucifer reveals he is immune to its effects, and it chronologically has not been seen since, although it has appeared in some time travel episodes.
In The French Mistake, after getting thrown into the "Real World", the directors discuss salvaging the footage of the brothers being thrown through the window by freeze-framing right before the interference. At the end of the episode, when they're getting thrown back into their own universe, how do you think they film it?
In the season seven finale, Dean and Castiel kill Dick Roman, but the backlash causes them to be sucked into Purgatory along with his soul.
Broken Angel: Castiel, more and more as Season 5 progresses, and to an extreme in the future timeline of episode 4 "The End".
As of Season 7, completely broken. And insane.
Season 8 took completely broken and insane Castiel, put him back together, just to break him even more fully as the season goes on, until by the finale he's managed to drag the entire Heavenly Host down with him too. The writers must hate the poor guy.
Broken Hero: Both Sam and Dean qualify, though their optimism has been somewhat drained by circumstance.
Cas (from season five onwards) and Bobby definitely qualify too. Although Bobby is probably the most functional of the group, he's still alcoholic and pretty messed up about his wife's death.
Cain and Abel: Hinted from day one. Season 5 tells us that Dean is supposed to be the vessel for the Archangel Michael, while Sam is supposed to be the vessel for Lucifer, and the older is supposed to kill the younger.
The Call Knows Where You Live: Happens twice in the pilot episode for Sam. First, his Dad goes missing and Dean comes to get him. He refuses that after killing the Monster of the Week, but watching his girlfriend burn up on the ceiling like his mother finally forces him to take the call for good.
In fact, any time either boy starts thinking about getting out of the business, they're dragged back in by rather brutal means. The Call doesn't just know where you are, it will stalk you from Hell and back. Literally. As in, angels besieged Hell and dragged Dean out because they had work for him. They dragged the brothers back from Heaven, too.
In seasons four and five and most of three, The Call is in fact semi-omniscient beings, requiring them to travel under a couple different types of mystic shielding. It steps up from hex bags to ribcages engraved in Enochian so Heaven and Lucifer wouldn't turn up and explain with nasty graphic examples why You Can't Fight Fate.
The other Call instances are mostly equally engineered, although the menace that sends soulless Sam into Dean's neighborhood in season six, dragging Dean slowly back onto the road after over a year of retirement, was just a monster seeking revenge on them for an earlier kill.
In "Home", Sam hands the kid he just rescued to the kid's big sister and says "Take your brother outside as fast as you can, and don’t look back," echoing his father's words and actions to Dean in the pilot.
Dean slams Sam against a wall in "Pilot" for questioning the family mission; Sam slams Dean against a wall in "Salvation" for doing the exact same thing.
In "What Is and What Should Never Be" there's a ton, visual and verbal, to the pilot episode: Mary going down the stairs (replaced by Sam), Dean and Sam fighting in the dark after Dean breaks in, "Lookin' for a beer," etc.
After finally killing Azazel at the end of Season 2, Dean tosses the Colt in the Impala's trunk, says, "We've got work to do," and closes the trunk, which is what Sam says and does (though not with the Colt) at the beginning of Season 1 after Azazel kills Mary and Jessica. This gets yet another Call Back when Dean is resurrected in Season 4 and Castiel tells him that he was brought back "Because we have work for you."
Season finales "Devil's Trap" and "No Rest For The Wicked" both involve Sam helplessly pinned to a wall by that season's Big Bad as said demon murders Dean in front of him.
Compare the Season 3 and Season 5 finales:
[hellhounds are ripping Dean to shreds, killing him]
Lilith: Yes! (tries to fry him)
[Lucifer snaps Bobby's neck like a twig, killing him]
Lucifer: Yes! (tries to beat him to death)
While trying to convince Sam to come with him, Dean admits that he doesn't want to do it alone. He mentions this again in season seven while on trial in "Defending Your Life".
Calling the Old Man Out: When Gabriel and Lucifer come face to face, this is the first thing Gabriel proceeds to do with his arrogant brother. "Lucifer, you're my brother, and I love you; but you are a great. Big. Bag o'dicks!" As Gabriel goes on, he insists that humans are not only better than Lucifer thinks, but deep down Lucifer is just jealous of 'Dad's' new creation. Lucifer does NOT take this well.
Bobby does this to his drunken, abusive father in "Death's Door", though technically it's an interactive memory of his long-dead father rather than the real thing.
The Case Of: The episode named "The Curious Case of Dean Winchester".
Cassandra Truth: Gordon was right all along about Sam. Subverted: while Sam definitely has darkness in him and accidentally started the Apocalypse, he sacrifices himself to save the world instead of siding with the demons or helping Lucifer take over the world.
Bobby's "Idjit"[sic]. Judging by the episode "Weekend at Bobby's," he apparently tends to say "balls" often when frustrated when he is alone (and thus has no one to say "idjit" to).
In one episode Bobby says "balls!", and then when later on Crowley is heard swearing, he says "bollocks!" Which is British slang for, well, "balls"...
"Son of a bitch!"
"Bitch!" - "Jerk!"
Dean refers to killing things as "ganking" them.
Caught with Your Pants Down: Implied in an episode, although when two male characters who are not having sex spend all their time together, it is to be expected.
Cessation Of Existence: As of the conclusion of Season 6, it's strongly implied (though not spelled out in so many words) that this is the fate of angels and demons who die in the show. (Unless God, or presumably Lucifer, takes a personal interest and brings them Back from the Dead.)
Chekhov's Gun: The Horsemen's rings are needed to trap Lucifer in Hell again.
Chekhov's Gunman: Hey, remember how throughout season five, the angels want Dean to be the vessel for Michael but he keeps rejecting them? Remember how the ability to be a vessel is a bloodline trait? Remember the Winchesters' half-brother Adam from a few seasons back who turned out to have been killed by a ghoul? Remember how the angels can bring people back from the dead?
Midway through Season Six we meet Bobby's friend Dr. Visyak, a professor with knowledge of the supernatural. In the penultimate episode of the season, we discover that she is an escapee from Purgatory, and is the only one who knows how to open a portal to it.
Chekhov's Skill: In "On the Head of a Pin", Alistair escapes from the devil's trap when Uriel manipulates a nearby water pipe. In "Abandon All Hope...," Cas pulls something similar on Meg to get out of the angel equivalent of said trap.
Chess with Death: Dean has one of these with Death: in exchange for bringing Sam's soul back to his body Dean has to do his job for a day. Dean ends up failing the test, but Death returns the soul anyway. Firstly because his real reason for the task was to show Dean what forces he was messing with by constantly resurrecting, and also because Sam and Dean's current investigation suited his purposes. He may have wanted a day off too.
Also, the whole premise of "The Curious Case Of Dean Winchester" revolves around this trope, even though the game of choice is poker.
The Chew Toy: With what they go through and the fact that they looked so darned pretty when being put through pain, both of them (but especially Dean) are walking a very fine line between this and pure-and-simple Woobification.
Christmas Episode: The Christmas episode A Very Supernatural Christmas has Evil Santa, sacrifices to gods (and what says Christmas more than watching someone's fingernail be torn off?) and a surprisingly effective ending. Sniff. And a tree decorated with air fresheners and fishing flies.
The writers managed to do this in the span of a single episode in season 5. It introduced Jesse Turner, a young boy explicitly identified as the Anti-Christ. This resulted from a union between a demon and a human, which somehow imbued him with high-level Reality Warper powers, an ability neither species displayed in any way. Possibly realizing how little sense it made that this would result in the most powerful character depicted in the show up to that point (with the possible exception of God) and the Story Breaker Power it entailed, the writers immediately sent the character off to nowhere, and he's never mentioned afterwards. It's technically also Put on a Bus, but it goes straight past even Long Bus Trip because everyone immediately forgets he ever existed at all.
During the first season, Sam meets a girl named Sarah who he manages to hit it off with, and she's notable for being just the only potential love interest Sam's ever had in the series who didn't have any major misfortune befalling her. She's briefly mentioned again in the following episode, but after that hasn't ever been brought up again.
She appears in the penultimate episode in Season eight, only to get immediately killed off.
Classical Movie Vampire: Beautifully (and hilariously) played with in "Monster Movie," this vampire turns out to be a lonely shapeshifter who admires the old Universal movie monsters.
Cold Turkeys Are Everywhere: Sam may have kicked the demon blood habit, but shanking demons for a living is doing nothing for his self-control.
Sam in season six. After getting his soul back from Death it is mentioned at the beginning of "Like a Virgin" that Sam has been "asleep" for almost ten days. Also at the beginning of the last episode of Season 6 "The Man Who Knew Too Much" as the mental wall keeping all of the hell memories at bay has been destroyed by Cass
Ron Reznick in "Nightshifter", who is convinced that the shapeshifter attacks he's been doing independent research on are caused by "mandroids".
In "Slash Fiction" paranoid whackjob Frank Devereaux doesn't put much stock in magic, but he's sure that "The government's been cloning people for years."
Continuity Drift: In the first season, vampires were shown to require blood in much smaller amounts than in other shows and movies (it took weeks for an entire coven to drink enough blood to kill two people). This is very difficult to reconcile with later appearances (i.e., they were somehow unable to drink cow blood without slaughtering the cows, despite having a huge supply and being easily able to go from cow to cow?).
It should be noted the vamps draining the cows are really brimming with blood lust because, while they just need blood to survive, they want human blood. The slaughtering of the cows may be less consequential and more a brutalization for the sake of brutalization, just to work out some of that tension. Besides, John's journal says "victims are taken to the nest to be drained for days or weeks." It doesn't specify the number of victims and it doesn't give a specific amount of time.
Sometime off-screen third season, the Winchester brothers each got a possession-blocking protective tattoo. From that first appearance onward, the tattoos can be seen from time to time over the collar of their shirts, though attention is almost never drawn to them again.
The tattoos were featured prominently in the season 8, episode 2 episode, and were used as a means to convince Kevin Tran and his mother to get similar tattoos to ward off possession.
Dean's amulet, which at this point has been missing from the show for two full years, appears on Dean's neck in a flashback in the season 7 episode "Repo Man."
The Coroner: A different one appears in many episodes (since they're moving all over the country working on cases) to explain to the Winchesters how the latest Victim of the Week met his or her gruesome end.
The Corruption: At the end of season four, Castiel tells Dean that consuming enough demon blood to kill Lilith will permanently mutate Sam into a monster. Possibly, God cleaning it out of his system prevented this.
Council of Angels: Heaven is apparently somewhat of a bureaucracy, as God has gone AWOL. In season six Heaven has descended into full scale civil war as Michael, its former leader (After God), has been trapped in Hell with Lucifer.
Creator Provincialism: It is...interesting...how the vast majority of the important events of the apocalypse take place in the continental United States. Kali is actually rather upset over this fact, and laments that "Westerners" are trying to take away her rightful spot in her own Apocalypse.
Possibly Justified. The Apocalypse is taking place in America because that's where Sam and Dean are. It wouldn't make a whole lot of sense for Lucifer to be doing his thing in the Middle East or Europe or anywhere else when his intended vessel lives in America. Now, the fact that Sam and Dean are American in the first place is all on the writers, but they can hardly be blamed for that.
Fortunately Castiel is on hand to pop over to the Holy Land to fetch any necessary Plot Device that the boys have need of, thus sparing them the onerous burden of international travel. As long as you have the right roadies you don't have to put any more effort into obtaining Holy Oil from Jerusalem than J-Lo does to getting Perrier from across town.
Crossover Cosmology: Just like All Myths Are True, so do all gods exist. Though they are apparently not all equal given how easily Lucifer mows down a dozen of them in "Hammer of the Gods."
Given the incessant complaints from pagan gods about losing their followers, it's likely that this is why the Christian/Jewish/Islamic God is capital-G God while the others are barely more than ordinary monsters
Crystal Dragon Jesus: Teetering on the precipice of this trope. While pretty much all of the Apocalypse storyline contains heavy use of individual elements and characters from Christian eschatology, the actual usage of God, Lucifer, the angels and the demons, to say nothing of the complete and utter absence of Jesus, really ends up presenting a pseudo-Christian world where most of the Biblical characters are really Captain Ersatz versions of the ones from the source material and their link to the religion overall is essentially as a fantasy remake of the original with updated, modernized, characters cherry-picked for dramatic convenience.
This happens several times with Alastair and Lilith, who pwn humans and angels alike to begin with, only for Sam to eventually kill them with his brain.
Anything attempting to take on an archangel ends up burned to dust with a simple touch, or exploded with a snap of the fingers. Lucifer slaughters pagan gods without breaking a sweat and then kills his brother - the archangel Gabriel - just as easily.
In the Season 6 finale the final battle between Castiel and Raphael ends up being like that. Amped up on purgatory souls, Castiel merely snaps his fingers and Raphael explodes into bloody goo.
Cut Apart: In "Folsom Prison Blues", Sam and Dean pull a jailbreak and go to the cemetery to destroy the remains of a nurse who is haunting the prison. The FBI is headed to the cemetery to recapture them. The camera cuts back and forth until it is revealed that the FBI was directed to the wrong cemetery.
The Cutie: Dean, before the issues came through thick and fast.
Possibly subverted too, seeing as how whenever the boys act all cutesy and 'normal' (Sam in the beginning of Season Three was quipping loads but falling apart trying to save Dean, and in the comedy episodes "Hollywood Babylon"/"Folsom Prison Blues", fans thinking that Dean was somehow really off were proven right in "What Is And What Should Never Be" when it was revealed that he had only been getting worse and more suicidal), something is usually very wrong with them.
Crowley. He correctly deduces Lucifer's inherent hatred of Demons, while his Demonic compatriots are all blind to this. In season 6 he takes the Winchesters very seriously as a threat and takes appropriate steps to foil them (including faking his own death), even pointing out all the Big Bads who were killed or defeated by failing to do just that. He uses the Winchesters to dismantle the Leviathans while staying on the sidelines. All this means he ends up outliving every other villain on the show.
Am I the only game piece on the board who doesn't underestimate those denim-wrapped nightmares?!
In "Season Seven, Time For a Wedding!", Becky doses Sam with love potion, and then conceals it from Dean with the knowledge she learned from reading the Supernatural novels. She instantly realizes the guy who's been giving her the love potion is a Crossroads Demon when he flashes his demon eyes at her, and is reluctant to accept this offered Deal with the Devil. And the devil in question has been taking advantage of loopholes in the deal.
"The Girl With the Dungeons and Dragons Tattoo", Charlie, learns about Leviathans, and reasonably assumes the person she got the info from is nuts. Then she accidentally learns they're real, and promptly tries to pack up and vanish. When the Winchesters show up, she reasonably assumes they're Leviathans, until they prove otherwise. For the duration of the episode, she tries to stick to her skill set instead of getting in fights, and leaves as soon as the episode is over. She literally Puts Herself On A Bus.
Misha Collins: (Typing into his phone) Ever. Get. The. Feeling. That. There's. Someone. In. The. Back. Seat? Frowny-face.
Dark and Troubled Past / Dysfunction Junction: if you haven't realised already that this show 'is this trope incarnate, then you obviously have not seen the first episode. Or any episode. Or were severely inebriated or high while watching... Or some combination of the above.
Even Bobby (previously the Only Sane Man... okay, still the Only Sane Man but for this show that doesn't say much for his comparative sanity) has massive problems.
The Dark Side Will Make You Forget: By the end of the fourth season, Sam pretty much runs out of legitimate excuses for his dark side-skirting behavior. He cops to this in early Season 5.
Darker and Edgier: Season 1 is more or less a show about two brothers trained to fight the supernatural, looking for their lost father. Then things go downhill.
Dating Catwoman: Sam and Ruby. The former is a hunter of supernatural monsters, the latter a demon. She eventually seduces him while mentoring him to kill other demons, and they start a physical relationship. In a later episode their foreplay jumps straight into Hemo Erotic territory when she lets him drink her blood, to which he is addicted. When he admits it to Dean, his brother is more than squicked out. One of the few examples in the series that isn't just one-sided Foe Yay from a villain towards one of the heroes.
Daywalking Vampire: Sunlight is not deadly to vampires, but it causes a nasty sunburn, thus they usually sleep during the day and hunt at night.
In several episodes, including "In My Time of Dying", "Crossroad Blues", and a major plot point in Season 3.
Recurs in season 5 with Bobby.
Crowley as well. Turns out he sold his soul while human for a "few more inches below the belt".
Death By Gluttony: Played for horror in the season 5 episode "My Bloody Valentine". The Horseman Famine compels a town full of people to eat and drink themselves to death in truly horrific ways. A young couple eat each other to death while having sex. One man binges on Twinkies until he can't swallow anymore, at which point he starts shoving them down his throat with a toilet brush. Another man wants fries so badly he shoves his hands and then his face into a fryer where the fries are still cooking. Even Castiel, an angel who doesn’t feel hunger, is compelled by Famine's presence to devour raw meat off the floor. Eventually Famine itself is defeated the same way: When he fails to tempt Sam with the blood of several demons, Famine eats the demons himself. Sam then exorcises the demons, ripping them right out of Famine's guts.
Death Faked for You: Dean and Sam after their run-ins with multiple law enforcement personnel. Most notably in Season Four and in season seven episode Slash Fiction.
Death Is Cheap: Played straight. Sam and Dean have died multiple times. Castiel has been dead at least three. One episode even had Sam and Dean killed by a couple of mooks trying to prevent the apocalypse. Dean even tells them he will be back and he will be pissed when he comes back. Bobby was even killed once or twice and got better.
Averted in "Mystery Spot", as none of Dean's onscreen deaths are dramatic/demonic-related. Especially his final death, where he gets shot by a mugger. No going out in a blaze of glory, it could have been easily prevented and nothing heroic about it whatsoever.
Played straight with many other deaths, most notably those of Jo and Ellen and Bobby Singer.
Dean's earliest brush is season one episode "Faith" when he learns that a faith healer saving him caused the death of a young man. After his Dad dies for him, he becomes tired of this life, selling his soul to get Sam back when he dies. By season five, Dean's even more tired of the life, even willing to be possessed by Michael to stop Lucifer.
In Season One, Sam was willing to die killing YED, and in season two, he wanted to be killed before his destiny could change him. Sam's entire season four arc was suicidal, as was season five, which ended with Sam jumping into Hell's solitary confinement to take Lucifer with him.
Debate and Switch: Frequently, usually in the form of whether to let someone who is doing bad things against their will (e.g., a werewolf) go, or kill them. The person usually dies or makes some sort of Heroic Sacrifice by episode's end.
Not quite lampshaded, but somewhat self-consciously averted in season 8's "bitten": the brothers briefly discuss whether the 'noble' werewolves can be left alone, decide in favor, and then sit quietly for a moment as if waiting for the last body to turn up.
While demonic possession features heavily, particularly in later seasons, only one of the brothers has ever been possessed, and that was only once. This is explained through the use of protective charms and, later, through magical protective tattoos.
Henrickson: Smart. How long have you had those [tattoos of magical possession protection]? Sam: Not long enough.
The shallow depth of field in most close shots is starting to work against them with the advent of HD - seeing Dean's stubble or Bobby's whiskers slip in and out of focus through the course of a scene as the cameraman fails to hold it just right is a common occurrence.
Dean crosses this in "On the Head of a Pin", and it takes angelic intervention to snap him out of it.
Bobby, Dean and Castiel all crash through this over the course of two consecutive episodes in Season 5. Sam probably crossed over at the end of Season 3.
Dean appears to have crossed it again in Season 7, to the point that he seems resigned to being blown up by Jo in Defending Your Life.
Devil but No God: Basically assumed true until Season 4, where angels of the Lord started showing up. God is confirmed to exist in Season 5, but he refuses to do anything.
Did Godzilla Just Punch Out Cthulhu: Demons, angels, archangels, the horsemen, God... The entire purpose of Team Free Will was to stop this happening between Michael and Lucifer. Because this would unfortunately have the tiny little side-effect of destroying nearly all life on Earth.
The Winchesters attempt it themselves in season 7's first episode in a last-ditch effort to stop the newly godlike Castiel. Death warns them that it won't end well for them, but he doesn't follow through on his threat after Castiel unbinds his restraints because the "mutated angel" is a bigger concern for him.
While at the time of Season Two Azazel was a very major threat, compared to what we've seen in the rest of the series, he could certainly be considered this now.
In Season Six, Crowley appears to be this to Eve, the Mother of All. Except, in actuality, she was the this to him.
In the season finale, it turns out that they were both this to Castiel, of all people.
Disney Death: The Season 5 finale, BIG TIME. First, Castiel and Bobby die abruptly and shockingly. And then Sam, one of the two main characters, apparently dies too - in what appears to be a chilling Kill 'em All ending. By the end of the episode, however, God brings Castiel back, Castiel resurrects Bobby and then, right before the credits, we see Sam is back too.
Disposable Woman: There are already two by the first episode. So basically, the show's entire plot was fueled by this trope. In fact, one wonders if there were any women on the writing team. Well, except for all the Fetish Fuel. (Although, to be fair, those two women were not forgotten. The men who loved them basically declared war on the forces of hell over them. Also, really, anyone who's not actually Sam or Dean dies, regardless of sex.)
Hell, even Sam and Dean tend to die every once in a while. They just keep coming back. Death Is Cheap for them.
One of the reasons women get treated the way they do is the fanbase and their "Keep those sluts away from our boys" mentality that pops up whenever strong (Or even merely decent) female characters appear in the show.
Distressed Damsel / Distressed Dude: So they might be big, tough men, but they've got nabbed enough times for this trope to apply. Sam is more often the one in peril, but when Dean is captured, he is usually captured for longer (for instance, in "Hunted"). Notable instances are when Sam is taken in "The Benders" (and then it was subverted by him getting out and Dean winding up being captured instead), in "Bloodlust" (although the vampires just wanted to talk with him and they release him afterwards), in "Home", "All Hell Breaks Loose, Part 1", "Long Distance Caller", "Time Is On My Side", and "Ghostfacers." Dean is captured in "Hunted", "Wendigo", "What Is And What Should Never Be", "Monster Movie", and "Scarecrow." Both are captured in "Skin" (Dean gets them out), "A Very Supernatural Christmas" (they somehow managed to get out off-screen) and "Shadow" (Sam gets them out, though Dean was pretty close). To list all the times one has been helpless/at the mercy of the MOTW so that the other can save him would be far too long especially in the case of Sam, Season 1 (and Dean managed to catch up in Seasons 2 and 3) — it's more than half the episodes. Not to mention that every episode there is at least one person (usually female) who needs to be rescued.
Does She Have A Sister: In "Tall Tales", Sam recounts how the past days went by to Bobby. When talking about the past night, he plays up his brother Dean's drunken sluttiness: Dean, well-intoxicated, is all over a random girl he picked up in the bar, and uses the inversion when he proudly declares to Sam that the girl has a sister and gives his own brother an obvious wink in case he didn't catch on yet. Sam isn't interested.
The male vampire in Fresh Blood is portrayed like a date-rape sexual predator.
Boris, the vampire in Live Free or Twi-Hard is presented like a drug pusher who exploits the glamorous modern views of modern vampire literature to have pretty boy vamps seduce impressionable girls, get them addicted to blood, and essentially force them into prostitution, to seduce the next batch of pretty boys to the cause.
Alistar: Go directly to Hell. Do not pass go, do not collect 200 dollars.
Do Not Taunt Cthulhu: Death embodies this trope, and everyone knows it. Dean, who has at one point threatened to hunt freakingGoddown like he hunts down everything else immediately shuts up in Death's presence. When they mess things up in Season 6 and the Leviathans get out of Purgatory, Death tells Dean what he needs to do to put them back in, Dean snarks for the first time in Death's presence. Death immediately turns around and says "Figure it out.". Dean shrinks down and obeys.
Tessa, one of the Reapers. Admittedly, some of the other Reapers we see range from creepy to outright scary, but Tessa appears to spirits as a gorgeous/hot, compassionate, and genuinely sweet servant of Death, and Sam and Dean even willingly save her from meeting a grisly fate in season four. Though during her role there, she's a bit more snippy than in her first appearance, mostly dismissing the bros when they try to help a dead young boy who has yet to pass on. The reason being, for the latter, was that she was supposed to take Dean, until he was brought back to life by Azazel, thanks to his dad making a deal.
In a later episode Dean wants Death's help to restore Sam's soul and Death gives him a test where Dean has to do Death's duties for a day. Dean fails the test but attempts to fix his mistake as much as he can. Death is impressed that Dean was able to understand how serious and important Death's job actually is and gives Sam his soul back.
Narrowly averted, probably by Author's Saving Throw, when Sam is implied to have had sex with Ruby, a demon — but it has been established that demons possess the bodies of living people, so Sam would be a rapist. Fan backlash was immediate and soon a flashback scene was written showing that Sam refused to have sex with Ruby until she explained that her body had just flatlined in the hospital when she took it over and there was nobody else in it... which of course has Unfortunate Implications in itself. If the body is technically dead, and Sam has sex with it, doesn't that mean...
In the episode "The French Mistake" where Sam and Dean get sent to the real world and it is implied that Sam gets intimate with his actor's wife. The Reality Subtext makes this merely amusing, but purely from an in-story perspective, Sam is a rapist.
The episodes "Wishful Thinking" and "Trial and Error" both have a man making a woman fall in love with him with magic (a magic coin and a Deal with the Devil. In both cases, the word "rape" isn't mentioned, and the situation's only treated as "How did this guy ended up with that girl?".
"Metamorphosis" ends with the boys both on a whole new level of fucked-up and their relationship at an all-time low, "Red Sky At Morning", "Jus in Bello" (demons kill nearly everyone), "Crossroad Blues", "What Is and What Should Never Be" (the bit where Dean decides to get back to reality is more of a weak and mewling 'yay' moment and Sam can't even convince him that what they do is worth it), "All Hell Breaks Loose, Part I" (Sam dies, but he recovers), "Heart" (Sam kills Madison, see Wangst), "Children Shouldn't Play With Dead Things" (Dean's crying over John's death and there's nothing Sam can say to make it alright), "Everybody Loves A Clown" (Dean shows how violently not okay he is by smashing his beloved car seventeen times), "In My Time of Dying" (John sells his soul to save Dean), and...this is too depressing. There are a lot of downer endings for this show. A lot.
The third season finale sets a whole new record by ending with Dean dead and in Hell, all of Sam's determination to save him over the course of the whole season thwarted. The season ends with Dean being torn apart by meat-hooks and desperately screaming for his brother over the credits. And no one knew if there would be another season because of the writers' strike.
"Heaven and Hell"
"Jump the Shark": Not only has Adam, the kid the brothers were trying to save, been dead all along, he actually was their brother. When Sam suggests calling in a favor from Castiel to bring him back, Dean replies it's better to leave him where he is because the world is going down the pooper pretty soon anyway.
The penultimate episode of Season 4, "When the Levee Breaks", laid a damn good claim to the record (Dean and Sam have a seemingly irrevocable parting of the ways), until "Lucifer Rising" managed to one-up it: God is M.I.A., the senior angels want the Apocalypse so they can beat the demons and care not about the collateral damage, Ruby is evil and has been manipulating Sam all along, and Lilith is the final seal and killing her will free Lucifer...which Sam learns about ten seconds after killing her. *gulp*
"Abandon All Hope...": Jo and Ellen die heroically to save Dean and Sam and give them a chance to kill Lucifer, which doesn't end up working. Oh, and Lucifer successfully raises Death, one of the Horsemen of the Apocalypse.
"Dark Side of The Moon": Well, if the episode starts with our heroes getting shot in the chest with a shotgun, it's a pretty good indicator of how the story's gonna go. Let's see, Dean is resentful of the fact that Sam's version of Heaven is completely made up of times that he was away from his family, Zachariah is personally out for vengeance upon Sam and Dean for moderately petty reasons, Joshua informs them that God knows, he just doesn't give a damn, Castiel, Dean and Sam basically give up their faith... But hey, at least we got some laughs out of Ash, right?
In season six episode "You Can't Handle the Truth": Sam's been acting weird all season not because he's a doppleganger or still possessed by Lucifer, but because he's emotionally dead. The episode ends with Dean beating him unconscious and not stopping. The next episode reveals that this is because Sam has no soul anymore.
"The Man Who Would Be King": With Castiel subsequently "betraying" the Winchesters and Dean begging Castiel to reconsider. To finish off your already distraught heart, they end with Castiel pleading with god to tell him if he's "traveling the wrong path" only to get no answer from god.
"The Man Who Knew Too Much" where Castiel's betrayal of the Winchesters is further cemented with him absorbing the souls of Purgatory and commanding the Winchesters and Bobby to bow down before him or face the consequences
In season seven's "Hello, Cruel World": The fates of Castiel and Bobby don't look so good, the Leviathans appear to be nigh invincible, Sam's hallucinations take a turn for the worse, and the episode ends with Sam and Dean being rushed to the very hospital that the monsters have taken over, unable to defend themselves. In addition, the brother's last safe haven, Bobby's house, has been torched.
"Death's Door": Bobby is dead and has yet to make the choice of whether or not to move on, Dean and Sam are totally and completely alone but for each other, they have no Cas, no Impala, and now Bobby is gone. And the Leviathans are running around, still thinking the Winchesters cannot stop them, and the only clue they have to stopping them is a group of numbers, 454895, that link to the Leviathan's plan that Bobby caught a glimpse of and was very scared by it. Dean and Sam have faced hardship but this is the harshest situation they've ever been in.
Dramatic Irony: After finding out what Castiel has done, Dean tells him he should have come to them. As revealed in the flashback in "The Man Who Would Be King", Castiel wanted to, but didn't because Dean was so happy living with Lisa and Ben and he didn't want to ruin that. But it was ruined anyway, thanks to him bringing Sam back to life (but without his soul).
Dream Sue: In "Tall Tales" (which is The Rashomon), Dean retells an evening in a bar to Bobby as if he is a romantic Dream Sue, with hints of being a perfect hunter as well. The entire setting is glamorized, and a girl just completely swoons over him and showers him with praise, while he insists that he has to do his "duty" of interviewing her because lifes are at stake. Sam by contrast is turned into a whiny jerk who simply wants to interrupt Dean and his lover, eventually just descending into whining "Blah Blah Blah".
Dress Up Episode: quite a few, given the number of different officials Sam and Dean end up posing as. Frontierland and Time After Time After Time are two of the most notable.
Dramatic Sit Down: Sam sits on the floor and stares on in horror after he realized that by killing Lilith, he set Lucifer free. Ruby monologues until Dean bursts in and they kill Ruby together.
Dean in "What Is And Never Should Be." Sort of. Damn alternate universes make these things confusing.
Another two for Dean would be "Croatoan" where he stays with his possibly psychotic-due-to-being-infected brother and "Faith" where he accepts his pending death and doesn't even run away when the reaper is after him. My God, that kid is screwed up.
Another for Sam would be the angst-filled, additional I Cannot Self-Terminate in "When the Levee Breaks." In the finale of Season Four, Sam doesn't believe he will—or want to—survive either.
Almost happens to Dean in "Point of No Return", also arguably Castiel.
Sam at the end of season five (with Dean and Bobby's reluctant approval!) in "Swan Song" (unless deliberately planning on jumping into Hell is seen as anything other than suicide).
Dean slips into suicidal Death Seeker mode quite often given the opportunity. He will sacrifice himself in a heart-beat to save someone and his complete lack of self-worth adds some very disturbing implications to his actions.
In Season 7, this seems to be where Sam's hallucinations are trying to push him - in Hello, Cruel World Lucifer suggests it three times.
Dean seems to have backslid into this again in the Season 7 episode Defending Your Life, where he is way too calm at the prospect of Jo killing him by gas explosion
Let's not forget the Suicide Bear in "Wishful thinking".
The standard Winchester coping mechanism. Especially Dean. This seems to be a common thing among hunters in general.
Castiel engages in this in "99 Problems", though it's tough for him due to his angelic constitution:
Castiel: I found a liquor store.
Castiel: And I drank it!
Later, Dean asks where he's been and he replies, "On a bender."
Drunk on the Dark Side: At the end of season six and the beginning of season seven, this has happened to Castiel after he absorbed all the souls in Purgatory to gain the power to prevent Archangel Raphael from restarting the Apocalypse. After proclaiming himself a new god, he threatens his friends' lives, goes out for some Disproportionate Revenge, and then accidentally releases unkillable monsters on the world.
Dying Curse: In "Death Takes A Holiday", the boys talk Pamela into helping them into the spirit realm, despite her objections that it is a stupidly dangerous endeavor. Sure enough, she gets hurt protecting their comatose bodies. As she dies, Pamela tells the Winchester boys to curse Bobby for introducing her to them.