Second Law of Metafictional Thermodynamics

""I do not understand why everything in this script must inevitably explode.""

- Teal'c, Stargate SG-1, on the script of Wormhole X-Treme: The movie.

The entropy of a fictional system whose writer is not in emotional equilibrium will tend to increase over time, approaching a maximum value at the writer's emotional equilibrium.

There's no other way to say it: writers like killing and destroying. Nothing makes them happier than having people die or Stuff Blowing Up. (In their writing, not in their real-world behavior. We're sure about this. Mostly.) It's the quickest way to get drama, too.

Unfortunately, writers cannot destroy all their fictional creations without ruining the story. Some of those creations have Contractual Immortality. Even when they don't, killing characters off or nuking cities can change the flow of a story in rather unfortunate ways. And destroying everything means there's no more story, and thus no more paychecks for the writer.

As a result, when there is anything expendable, writers will expend it. If the writer can bring people back to life by pushing the Reset Button, then people will die as long as the button is there. If a city has been evacuated, that city will go down in flames. Atomic flames, preferably. If it hasn't been evacuated, the writers can blow it up anyway if no named characters are there. It's not like readers will be upset, right? After all, A Million Is a Statistic.

The less often the writers get to do this, the more pyrotechnics they pack in. When everything is expendable (like in a show with Negative Continuity), the writers will increase their system's entropy at a leisurely pace. One death an episode or so will do. If almost everything has Contractual Immortality, then killable characters and inflammable places are rare treats, and the writers will spring on them like the proverbial hungry wolves on a sheep.

At times, some writers seem to be working out their stress by destroying fictional people and places. The carnage is always greatest at the moment the writer gets better, since they will increase the entropy until their self-therapy finally works. Needless to say, Creator Breakdown almost inevitably leads to higher entropy.

This is the reason for the following tropes:
 * All the Myriad Ways
 * Anyone Can Die
 * Battle Royale With Cheese
 * C-List Fodder
 * Cloning Blues
 * Conveniently Empty Building
 * It's Going Down
 * Kill'Em All
 * Opening a Can of Clones
 * Reset Button
 * Stuffed Into the Fridge
 * Tonight Someone Dies
 * Throwaway Country

Anime/Manga

 * Neon Genesis Evangelion is actually famous for its Creator Breakdown and subsequent . It's a great example of this trope even before the ending, with more and more damage being done to Tokyo 3 and the cast each passing episode. This could also be tied to Hideaki Anno's building depression.

Comic Books

 * Dark Age comics seemed to go through a period when blowing up or wrecking cities, or killing off characters, was the flavor of the decade. Especially DC with its Coast City debacle, Gotham City's "No Man's Land", and three-quarters of Metropolis being wrecked. And Montevideo (wonder how the real city took the news?). The capitol of Nebraska gets nuked by an alien thingy, with the after effects blowing over half of Smallville. They seem to be reverting to this again with several throw-away countries being violently depopulated and Bludhaven drowning in toxic chemicals/going boom.
 * Random worldwide massacres. Maggedon comes along, thousands croak in the affects of his defeat. Cyborg comes back to life, eats the moon, the world shakes and shimmies and buildings collapse. 'Infinite Crisis' had hurricanes chowing down all over the world, entire cities flood and nearly every volcano ever blowing its top.
 * Gotham City in the comics. Every time The Joker slips loose from Arkham Asylum or the Scarecrow gets his crazy on or heck, there's just a party, something shows up and turns hundreds of people into crispy fried corpses. And the police officers...does anyone train them? They go down dead when looked at hard.
 * During the mostly-Superman event Our Worlds at War, the city of Topeka, Kansas was completely destroyed. Unlike Marvel and their New York setting, DC apparently didn't care whether the "Topeka" depicted in the book actually resembled the real life Topeka.
 * Marvel also had its bloodbaths, with Manhattan being badly damaged by Onslaught (and later, mostly leveled by Magneto), Carnage and his troops turning the streets into killing fields and the island of Genosha and its sixteen million mutants being killed.
 * For this and many other disasters, the regular Marvel Universe has 'Damage Control', a company that can apparently rebuild entire cities just by ... um ... being awesome. Or something. Don't look too closely.
 * Ultimate Marvel has had millions killed by the various alien invasions (especially the worldwide mass suicides during Ultimate Galactus), Magneto's Brotherhood attacks, Proteus' Reality Warper rampage, and the Liberators' brief conquest of the United States.
 * Let's not forget the Civil War arc, where The Hulk caused a ludicrous amount of damage to New York City. Admittedly, it was (somewhat) justified. Well, kinda.
 * It gets bad whenever Marvel has the heavier cosmic characters go at it. In one story simply waking the ruling celestial destroyed two galaxies. Even planet eater Galactus was having trouble holding it in.
 * Infinity Gauntlet was an example of the reset button. Iron Man loses his head, Spider-Man's head is crushed, Thor is turned to stone, half the universe suddenly dies etc.
 * Judge Dredd also followed this trend; from the early comics, where a Judge would risk his life to save a single child, to later when it was acceptable behavior to gun down one innocent if it meant hitting the two perps next to them, to some storylines where wholesale carnage was status quo. This troper was particularly offended by Graveyard Shift, which was about the riots and carnage in Mega-City that cost thousands of lives and was assumed to happen nightly. After a while you stopped caring.

Film

 * Resident Evil Apocalypse: Alice and company are safely escaping in the helicopter. 99.44% of the rest of the city is zombies anyway.
 * Return of the Living Dead The army has no idea how to get rid of the zombies. They bomb the whole town. This proves to be ill-advised.
 * Subverted in Outbreak. The viewers were given plenty of information about the residents of the town about to be bombed. So naturally the day is saved.
 * In Alien vs Predator: Requiem,
 * In relation to the comics above, The Dark Knight is an exception. In the comics, it's a rare, rare person who escapes the attentions of The Joker alive, much less un-maimed. In the movie, many do so, even cops who are usually the first to go.
 * The Dark Knight and Batman Begins seem to be working very hard to present Batman and his world in a 'realistic' setting. In a superheroic setting where the main characters are far more powerful and capable than normal humans, The Joker can go omnicidal easily enough. But when you present Joker as a 'realistic' psycho, he's more limited.
 * More limited, but limited in a way that still let him be way more awesome.
 * Anything not critical (anymore) to the plot in Armageddon blows up. The spacecraft visit MIR for refueling; It blows up right after they're done. There are 2 spacecrafts; One crashes. The drill of the crashed spacecraft survives; The one from the other spacecraft blows up.

Literature

 * Word of God states that this is the reason  in The Stand.
 * E M Dutch does this in Another Day Another Nightmare. Every time she reached a plot hole, or suffered from writers' block, she killed someone off. In increasingly imaginative ways, including a flock of exploding pink budgies parakeets. I really wish I was kidding. Apparently, the (as yet unpublished) sequel(s) contains more of the same, to the extent that the author has stated she can't write another in the series because everyone with unresolved plot has already been killed off...
 * Douglas Adams was having a really horrible year when he wrote Mostly Harmless, so he not only, but by the end of the book he actually.

Live Action TV

 * 24 without a doubt. The writers seem to create characters, buildings, and whole cities for the express purpose of killing or destroying them later.
 * It becomes clear that there are so many people with abilities in Heroes so that the writers have lots of cool people to kill off in shocking ways. They take it one step further with their alternate futures where something is always about to be blown-up, a virus will kill everyone, or some other cataclysm will take place, but thanks the Reset Button, it never comes to pass. This of course allows for more alternate timelines to be created and averted.
 * Beginning as a strange but mostly plausible story about what happens to retired secret agents, The Prisoner gets more bizarre over time until the last episode leaves viewers utterly dumbfounded.
 * The intro sequence of Seven Days (where the entire plot -is- the Reset Button) uses a shot of missiles striking the White House. That was in the pilot episode, and things only get more dangerous from there.
 * Every Alternate Universe episode of Stargate SG-1, most prominently in "There But For The Grace Of God," in which all main characters bar Daniel Jackson are killed and the Earth is taken over by Apophis and 2010 in which all main characters are killed and 90% of Earth's population has been sterilized by an alien race that plans to make us slaves.
 * Martin Gero, one of the writers on Stargate Atlantis has said in commentaries that he killed someone in every episode he wrote in season one since he was alone in a new city and girlfriend-less. Following with the trope, when he wrote season two episodes he was happy and in love so the carnage was scaled back.
 * Let's not forget that every member of SG-1 was also killed at one point (and later brought back to life). Special mention goes to Daniel who was killed off the most.
 * Buffy the Vampire Slayer liked to end seasons this way once a particular set became expendable: See Sunnydale High, the Initiative, to a lesser extent The Magic Box, and in the series finale the entire city of Sunnydale.
 * Story-wise, the entire city was designed so expendable humans could be safely eaten.

Western Animation

 * In Aqua Teen Hunger Force, anything that touches Master Shake and then a surface (wall, ceiling, or floor) will explode. With no effects on anything around it. Fans often speculate that this is Shake's superpower. Fortunately (for Meat Wad at least), Shake seems entirely unaware of this effect.