"In other words, the story does not trick the player, it is the player that tricks himself."
CAUTION: Read this article carefully before using it—if you don't, you'll probably mistake it for Not a Subversion.
Basically, this is playing bait and switch with a trope. A work makes you think a trope is going to happen, but it doesn't.
But how could people know a trope is going to happen? Well tropes live in the minds of the audience. As such, sufficiently Genre Savvy (or Trope Savvy) audience members can predict a familiar trope coming based on the hints dropped by the writer. So when the writer decides to build on this expectation, only to reveal that the expected "trope" was a Red Herring while an entirely different situation results, you have a Subverted Trope.
Phrased another way, the work is ultimately revealed not to be using the trope at all, but in the meantime was played up to look like it was.
This is one method of leveraging a trope to give a story texture. It certainly isn't the only way.
A subversion has two mandatory segments. First, the expectation is set up that something we have seen plenty of times before is coming, then that set-up is paid off with something else entirely. The set-up is a trope; the "something else" is the subversion. It is a deliberate act on the part of the characters, as though they are expecting the trope themselves.
To put this another way, a trope of the form "X are often Y" is not subverted by every X you can think of that isn't Y. If someone is murdered and there's a butler around, but he didn't do it, that's not automatically a subversion of The Butler Did It. But if the writer makes it look like a typical example of The Butler Did It, then reveals he didn't, that's a subversion.
A full comparison could go something like this: A car chase is in progress at reckless speeds. The camera cuts to some workers carrying a Sheet of Glass, then cuts back to the panicked driver headed towards the workers. It seems pretty obvious that the driver is going to smash the glass sheet into a million fragments ... or is it?
- If the car drives through the pane of glass, it's played straight.
- If the car misses the pane of glass, it's subverted.
- If something else causes the glass to be broken before the car can even make it to where the glass pane broke, it's also subverted.
- Another subversion is if the car hits, but somehow the car phases through and neither the glass nor the car is broken.
- If the car misses the pane of glass but something else causes the glass to be broken, it's a double subversion.
- If the car hits the pane of glass, and the result is that the glass merely has a car-shaped hole in it, that's downplayed (and also Played for Laughs, but that's another matter.)
- However, if the car hits the pane of glass, and the result is that the glass merely has a car-shaped hole in it, but the pane of glass collapsed on itself, it's either played straight or a double subversion (And also breaking a downplay).
- If the car hits the glass, but it's the car that shatters (instead of the glass), it's inverted (and a very shoddily-built car at that).
- If there is no pane of glass at all, it's averted.
In addition, kindly avoid using "subverted brutally" or "subverted hard" when describing the manner in which a trope is subverted. There is no guarantee that your example was subverted any harder than the previous one.
Bear in mind that, just as Tropes Are Not Bad, subversions are not automatically good, witty, clever, or original; conversely, don't hesitate to add a subversion (that's actually there) just because you think the work is inane and stupid.
Meta Trope Intro compares this with many other ways that a trope can be used.
Every trope page has 'subverted in...' somewhere on it. Please, apply the Wiki Magic!
- Watchmen: Adrian Veidt is set up to be the ultimate in Ambiguously Gay, with all of the preening attention to his own physical appearance and lack of fighting ability that is associated with that trope. Then somebody tries to shoot him, and he responds by picking up an eight-foot-tall floor lamp and using it to bash the gunman into a fountain, then climbing in after him and demanding to know who sent him while shaking and choking him. Subverted even further when we find out that Veidt hired the assassin himself as a red herring, and when Veidt proceeds to beat the everloving crap out of Nite Owl and Rorschach simultaneously, and then proves his skill further by catching a bullet.
- The ending can be seen as a major subversion Rorschach and Nite Owl confront the now realized-to-be-the-evil-villain Adrian, he explains his master plan and when told that he will be stopped, he informs them that he carried out his plan before they even got there.
- In the season 2 finale of Carnivale, Jonesy strikes Varlyn Stroud unconscious with a log of wood. He then runs into the house that Varlyn was about to enter and rescues Sophie, leaving Varlyn and Varlyns handgun unattended right outside the door. Seconds later, Josey gets shot... By Sophie.
- This is a staple of much of the comedy on Mongrels; starting out with what seems to be a buildup to an obvious joke only to quickly turn it around (often lampshading it in the process), like so:
Nelson: How did you get these documents?
- Lemon Demon's Being a Rock Star handily subverts the Rockstar Song trope. It starts with some generic lyrics about rockstardom, but rapidly switches to insulting the concept in the space of a verse or two.
- PDQ Bach's "Concerto for Horn and Hardart" contains a subversion of the Theme with Variations.
Peter Schickele: The striking thing about the middle movement, the Theme with Variations, is that the variations have nothing whatsoever to do with the theme. Now, that's one of those things that everybody takes for granted, but why not? I mean... This is apparently variations on some other theme. Perhaps we'll turn that other work up someday.
- George the Dragon subverts the expectations of dragon dietary preferences.
- Blur the Lines subverts Stuffed Into the Fridge when Drew receives a present that the giver implies is the head of his lover, Rick. After crying out because he thinks his lover is dead, Rick walks up behind him and says, "What? Why are you screaming?" 
- Robespierre in Rusty and Co. looks to be a very archetypal Dumb Muscle type of character for a good part of the comic, above all due to his speech pattern, until the baseball arc where he shows some surprising tactical thinking and cunning as well as a very sharp wit.
- Superman: The Animated Series plays straight and subverts many tropes, but it is noteworthy the way it handled Bury Your Gays. Maggie Sawyer was primarily a victim of Hide Your Lesbians, up until the second season episode Apokolips...Now! there had not been any hints to her orientation in the comics, but she seemed to be legitimately set up for death. When she is attacked by Intergang she is thrown from her car in a fiery explosion and she is shown horribly burned beneath a crushing pile of rubble, noticeably without a blinking eye or moving fingers. It looks like she is Killed Off for Real, especially when Dan Turpin starts calling the attackers "murderers" while screaming at them, except a later scene reveals her to be Not Quite Dead. This later scene, which revealed that she had survived and thus subverted the Bury Your Gays trope, also provided the first ever hint at her sexuality when she is visited in the hospital by a woman that the DVD commentary reveals is Toby Raines, her partner in the comics. So, Maggie not only survives the attack, which is a straight subversion of the Bury Your Gays premise, but the setup actually lead to a (partial) revelation of her sexuality, something this trope is usually invoked specifically to avoid, making it also an inversion.
- The Simpsons is the master of the subverted trope. One example of many is in the episode "Monty Can't Buy Me Love," where Cue the Flying Pigs is subverted when Mr. Burns and Smithers enter a book store:
Burns: Books and cocoa in the same store? What's next, a talking banana?
- In Vino Veritas is subverted in the episode "Mountain of Madness," where a park ranger enters a cabin and finds it full of partying employees from the nuclear plant.
Ranger: Hey, what is going on here? Who are you people? This is a lookout post. Where is Ranger Mc Fadden?
- A third example, also from "Monty Can't Buy Me Love," is when Mr. Burns, Homer et al have finally found the Loch Ness monster, who proves impossible to subdue. Finally Mr. Burns walks toward the monster with a stern look in his face. We expect an epic fight where Mr. Burns is revealed as a Badass Grandpa handing out an unexpected ass-kicking—but instead the scene cuts to the team's helicopter in the air, with Nessie tied up and swinging below. Mr. Burns explains to the admiring team:
Burns: I was a little worried when he swallowed me, but ... well, you saw the rest.
- Another episode subverts the car driving towards glass example mentioned above. In this case, the car hits the glass, but simply knocks it down flat on the ground and drives over it. The workers then pick the glass back up noting "wow, tough glass."
- The Simpsons really loves playing subversions for laughs. Another example: When the Simpsons are kicked out of their house, Homer remarks: "Well, at least it's not raining!" Beat. "See, it's not raining."
- In Family Guy, Peter has just launched himself from a cannon. Cut to a living room:
Guy: Great, I've got all my dominoes set up exactly how I want them, next to the good china. Now I'll just place this priceless faberge egg next to my newborn hemophiliac baby....