Two Rights Make a Wrong

""It is a military fact that Grock failed, because two of his soldiers obeyed him. It is a military fact that he might have succeeded, if one of them had disobeyed him.""

- G. K. Chesterton, The Paradoxes of Mr Pond

Even the best laid plans can have a chance of failure. Maybe something was overlooked. Someone with obscene amounts of resources would start a new plan from stage one, but often that's not possible. The previous action had some success, and to implement a completely new path could require a lot of resources and time, which may not available. An entirely new option would be like using a new fuel source for your house every time a light bulb goes out.

A rational response would be to Set Right What Once Went Wrong, and just fix what was already there, making sure that the problem that arose is less likely to happen again. Unfortunately, it still will, specifically because of the fix.

When someone tries to solve a problem, the solutions counteract each other, making a negative outcome easier (or possible). Depending on the consequences, this could be Played for Laughs or Played for Drama, or both. Simplified, it could be like flipping a switch, then flipping it again, not realizing it had been done the first time.

Consider Didn't Think This Through, when one person does it. Because this requires some knowledge of what went wrong previously, the fixes may have been thought through, just not for every possible interaction, or maybe even overlooking exceedingly obvious interactions.

Compare Tragic Mistake, Hoist by His Own Petard, Didn't See That Coming, Right Hand Versus Left Hand and "Gift of the Magi" Plot. Alternatively, "Nice job breaking it, hero/fixing it, villain!". Dick Dastardly Stops to Cheat is a Villain Ball subtrope. The Poisoned Chalice Switcheroo can often lead to this. If pulling this on another party is part of a gambit, it can overlap with Kansas City Shuffle.

Since at least a temporary Bad Ending is the point of this trope, expect some spoilers.

Anime & Manga

 * In Death Note, both Light and Mikami decide to kill after she gets kidnapped and has outlived her usefulness. Unfortunately for Light, and fortunately for Near, Mikami's decision to kill her on his own without checking with Light first

Film

 * In Diamonds Are Forever, James Bond and the Bond girl both have the idea of swapping the control tape for Blofeld's Kill Sat with a fake. Result: the real tape gets swapped right back into the machine.
 * In the political satire The Rise and Rise of Michael Rimmer, just as the eponymous Rimmer is about to stage a popular coup one of the people he's pissed off attempts to shoot him from a high window while another is preparing to throw a bomb. Unfortunately the gunman falls out of the window onto the bomber, and the bomb goes off next to them.

Literature

 * In one of the Star Trek novels written by William Shatner, two independent groups are trying to rescue hostages from a base in low orbit around a planet. Saving them requires destroying either the main power generator or the backup power generator -- but not both, as that would cause the base to lose orbit and everyone to die. One of the groups chooses to disable the main generator for their rescue attempt, while the other group chooses to disable to backup generator. Both put their plans into motion at exactly the same time. Tragedy results.
 * In the Doctor Who Expanded Universe novel Cold Fusion the Doctor does this to himself. There are some galaxy shattering grenades that can be disarmed by reversing the polarity of the neutron flow, which he does so he can fake out the villain by pretending that they've won when they send the duds to the target. Then his past self finds the grenades and re-reverses the polarity thinking he's the one disarming them. Which means the bombs are live when sent to their target.
 * One of G. K. Chesterton's Paradoxes of Mr Pond, "The Three Horsemen of the Apocalypse", concerns a field marshal whose soldiers were too eager to obey his orders, with the result that the orders were not carried out. If only one man had been that loyal it would have worked, but with two soldiers determined to fulfill his orders to execute a poet, the man ends up released.
 * The Russian fable about Yeruslan Lazarevich includes him battling a king who can only be killed by a particular sword. The sword lies under the head of a giant who already tried to fight him. Fortunately for Yeruslan, the head is still alive, and warns him of the catch - strike the king only once. A second strike will heal him.

Live Action TV

 * In one Mad About You. Paul & Jamie left their apartment in the middle of the night still in their pajamas. Paul "pushed the little button" which deactivates the latch lock on the door so that they could get back in and not have to take their keys. Jamie doesn't know that Paul did that so she pushes the little button too, so now they're locked out but don't discover that until they come back from whatever adventure they had.
 * Several episodes of The Outer Limits Revival feature this as the Cruel Twist Ending.
 * On an episode of Gilligans Island, a homing pigeon landed on the island, and the gang realized they could send a note home with it. The Professor said the pigeon was too thin to make the trip home, however, and needed to fatten up with a proper diet and exercise. But the rest of the gang, impatient to leave, overfed the bird, and the next morning the bird was too fat to make the trip.

Video Games

 * Portal 2: No portal surfaces = good; bombs for enemy and bomb protection for the boss = also good; combining the two and being tricked into releasing portal surfaces = BAD..
 * The bombs were also wholly redundant based on the immediate flow of neurotoxin. More patience would have meant a win anyway.
 * And then.

Western Animation

 * The Powerpuff Girls episode "Monkey See, Doggy Two": butt plating = good on its own, and that would've been all that was needed. Not turning the girls into dogs was a pretty bad decision, but turning them into dogs didn't work the first time. However, that problem would've been remedied by the butt plating. Telling the girls how he fixed his mistakes = pretty stupid. All three combined just lead to a normal beatdown, plus a possible unhappy ending.
 * In The Simpsons, Apu and his wife Mnajula end up with octuplets, almost going broke due to the resulting expenses, when every member of the Simpson family independently decides to help along their desire to conceive by secretly slipping them fertility drugs.
 * A SpongeBob SquarePants episode featured a giant worm terrorizing Bikini Bottom and Sandy decided to go after it. Not believing her chances of winning, the citizens pushed the town into another area. Guess where Sandy drove the worm.