There's a whole genre of sci-fi that has a major premise as "humanity is the most powerful/dominating/victorious species in the cosmos...and that's not a compliment". I always understood that to be a facet of HFY, but per this sub's description HFY should be "uplifting".

Like, a story where aliens try to invade Earth and we kick their asses is definitely HFY. But what if we then enslave the survivors of the alien horde? What if we reverse engineer their tech, go to their homeworld, and nuke their planet? What if we tailor a virus to their genome and purge the galaxy of their entire species, and their little alien babies die screaming in their little alien cribs?

Is that HFY?

Not mine, but by several people on tumblr (Archive.org link in case the tumblr link pushes a sign in)

Undocumented Buttons

"Globtroq, what are these buttons for?" asked the spindly Ognimalf named Bert, holding the pilot chair upside-down to his obese Adnap buddy, Globtroq. The unlikely duo owned a run-down repair shop for small spacecraft in the remote corners of the galaxy. Their business was far from glamorous; in fact, they spent most of their days fiddling with spaceships that had been acquired in rather dubious ways.

Globtroq looked at the buttons: two green, two pink, one grayish. They were cleverly concealed beneath the obviously human pilot chair.

“Dunno…” Globtroq mumbled, reaching towards the buttons.

"Hell no, don't touch them!" Bert shrieked, pulling the chair away. "Last time you pressed an undocumented button in a human spaceship, you emptied the entire septic tank into our garage!"

“Uhm, sorry, instinct…” grunted the portly Globtroq “Never seen such buttons. Don’t know.”

Bert held the chair overhead, turned it around, then put it under the examination lamp and used the sonic scanner on it, looking for clues.

"This doesn't make sense," he snorted in annoyance. "No labels, no cables. What are these buttons for?"

The stubby Globtroq climbed on top of table and peered at the pilot chair. “Dunno… but they hid them well. Must be something very special. You know how humans are. Always doing something incredible stupid in a brilliant way or something brilliant in an incredible stupid way.”

Meanwhile Bert flipped through the printed manual, gasping in frustration. "Crap! This manual is printed in 24 different human languages, and I can't read a single one of them. Globtroq, get me a dictionary."

…ten hours later...

"...and this button controls the windshield wiper speed," Bert finished, tossing the manual annoyed into a corner.

Globtroq, scratching his fluffy behind, asked cluelessly, "Uh, Bert, I dozed off, did they mention anything about those buttons?"

“NOTHING!” squeaked Bert “They fucking wrote NOTHING about buttons under the pilots chair!”

"That's odd," Globtroq shrugged.

“That’s not odd, that’s steaming Nacluv Shit!” a pretty pissed Bert snorted. Then he declared, holding the thick manual in his hand, "I'm going to translate the entire manual until I find out what these buttons are for!"

"That's only the Quick-start Manual," Globtroq dryly stated, lifting a massive box filled with thousands of pages onto the table.

The spindly Ognimalf suddenly grasped the enormity of the task before him, and the vibrant pink in his feathers faded away...

…six days later…

Bert's feathers had turned almost grayish as he studied the endless stack of manuals in front of him. His annoyed brooding was interrupted when Globtroq startled him by entering without knocking. As usual.

"Globtroq, what the... who is that alien?" Bert asked, pointing at a newcomer.

The fatty pointed back at his companion and replied dryly, “I found a human. It is a human pilot chair. A human should know about the buttons. Human, that spindly dude is Bert. Bert is not his real name but I am unable to pronounce his real name. Bert, that is human.”

The human let out an amused chuckle and nodded at the spindly Ognimalf. "Hey there, I'm Max. Well, that's not my full name either, but Globtroq can't wrap his tongue around..."

Max couldn't finish his sentence as Bert interrupted him, exclaiming, "Oh, by the feather gods! A human! I was going bonkers! Look, we've got this pilot chair from a human spaceship, and it has buttons that are nowhere to be found in any documentation. We've been at it for nearly a week, and…"

"Hold on, buddy. I'm just a tourist; I know zilch about piloting a spaceship..." Max explained. However, seeing the color drain from Bert's feathers, he felt a pang of sympathy for the alien avian. "...but hey, I'll take a look and see what I can see, alright?"

Globtroq happily led Max to the chair and showed him the buttons, while Bert looked at the ceiling and wallowed in despair.

“Uhm, I have an assumption” Max stated “can I visit the cockpit for a moment?”

A sulking Bert and an overjoyed Globtroq led him into the small cockpit, where Max promptly opened the glove compartment, retrieved something, asking, “You wouldn’t mind if I take one of these human snacks?”

Bert just continued sulking while Globtroq happily took one of the small snacks offered by Max.

"Tasty," Globtroq remarked.

Max nodded in agreement and returned to the pilot chair “Cherry flavor. A bit past its prime, but still good.”

Bert reluctantly followed, trying to sulk as hard as possible.

And then, to everyone's surprise, Max spat out his snack and pressed it alongside the other buttons under the pilot's chair. It stuck.

“Gentlebeings.” Max announced dramatically, "the individual who sold you this heap of junk was a downright repulsive being. These buttons? They're dried-up globs of chewing gum."

The End ---

Originally written by injuries-in-dust on tumblr (non-tumblr link in case tumblr pushes you to make an account), not by me.

“Boredom is a dangerous thing to a human.”

“I don’t understand,” Chuul’s mandibles clicked nervously, “why not simply take the tool from the human.”

Minxx’s antennae stood straight up, a sign of shock, fear, or surprise, “You don’t simply take something from a human. If you do they will either turn the ship upside down trying to find it again, or they will replace it with something else that will lead to more destruction.

“I speak quite literally by the way. Human-Mark used to have a tool he called an “Hex Key” he used it to remove the doors to the clothing storage areas in his quarters because he was bored. When he lost it he literally turned the ship upside down by reversing the gravity.”

Chuul’s tentacles curled up defensively, “Gravity controls are locked, how-”

“No one knows how.” Minxx shook her small wings as the memory of suddenly falling upwards returned to her. “but his reasoning was that the tool would fall out of whatever hiding place it had come to rest within. He had not considered that all tables, chairs, equipment, and personnel, would also fall. It took weeks to clean.”

To be fair to the human, Mark had only intended to reverse the gravity in his own quarters but had, quote, “pushed the wrong button.” A sentence which would send fear through any intelligent creature in the known galaxy. To be completely unfair to the human, there were still stains on the ceiling in almost every room of the ship from dropped food, chemicals, various other liquids, and even a couple of empty bowels. Some races just didn’t find the idea of resting comfortably in their sleeping quarters, only to be suddenly awakened as they fell ten feet toward a ceiling which had now become a floor. Mark was no longer allowed near environmental controls.

Minxx continued, “He did not find this “Hex Key.” However, he did find the screwdriver and it seemed to please him when an owner was not located. The captain let him keep it since it seemed that it would keep him from doing any more strange things to locate his original lost tool. We did not consider-” she trailed off as her wings quivered again.

There was silence between them for a few moments, Minxx was almost unwilling to continue and Chuul was almost too afraid to press for more details. Slowly, but surely, Minxx calmed herself enough to speak again. “we did not consider what he may be able to do when armed with a leverage optimiser.”

“We were given shore leave while the ship was being fixed after the gravity incident. Thank goodness the captain took out act’s-of-human insurance or it would have cost the profits from our next five cargo hauls.” The premiums were high, but it was worth it. “After 14 rotations, human-Mark began to complain over the lack of stimulation, he called it “bored.” On the 15th rotation he disappeared for some time and he had hoped he had found some new activity to occupy his time.”

Chuul did, but at the same time didn’t, want to know, “Had he?”

Minxx waved her antennae in confirmation, “he had. He was located in one of the cargo holds, using the screwdriver to dismantle one of the mining probes. To, quote “see how it worked.” It was almost 90% deconstructed.”

Mark had claimed it was almost 10% REconstructed, as he was trying to put it back together again, but couldn't quite remember where all the parts went. In Mark’s words, the captain was a “glass half-empty kinda guy” (whatever that meant) and wrote DEconstructed on the claim form for a replacement probe.

Chuul’s natural camouflage kicked in and they took on the colour of the chair they were sitting on. “Those probes have no screws for the leverage optimiser to use, how did he-”

Minxx’s wings shivered again, “no one knows how. He just did.”

Chuul was silent for a moment. He’d never served on a ship with a human before. He’d heard they made things “interesting” and if you ever got into trouble, a human was the very best thing to ever have on your side. It was why they were so many job opportunities for humans in the alliance. All the same...the thought of a human causing such damage and destruction just because of a lack of mental, or physical, stimulation was a more than a little frightening. What if the human wanted to see how the engines worked, or the weapons?!! “Maybe I should transfer to another ship.”

Minxx’s antennae curled, a smile to her race. “You are safe. The captain has found a way to occupy our humans free time. During our last stopover, he commissioned a shiny orb be constructed.”

Chuul coked their head, “what is a shiny orb?”

Minxx’s curled antennae moved up an down; a sign of mild laughter. “It is nothing. A sphere made of shiny metals, humans do like shiny things, roughly two feet diameter made of a collection of gears, levers, screws and switches which appear complex and should have a function, but do entirely nothing. The captain handed it to Human-Mark and stated: “see if you can fix this.” and Mark has been “tinkering” with it during his off-duty hours for almost 24 rotations now. He can take it apart and rebuild it as many times as he likes, but it will never perform any task.”

Chuul was just thinking about how their captain must be a genius, when the door to the mess hall opened and Human-Mark entered. He was carrying the shiny orb under one arm, and his screwdriver in the other hand. He looked around, seemingly not noticing any of the crew members. He smiled when he spotted an empty liquid container and sat down at the table with the cup.

Chuul and Minxx watched curiously as Mark set the orb on the table in front of the cup. He used the screwdriver to tighten one small screw and flipped a switch. At once there was a whirring and clicking of clockwork, a blinking of lights hidden in the depths of the machine and even a TING from a small bell. Then a small funnel-shaped piece of metal opened up in the side of the machine and poured a small amount of hot, black, liquid into the cup.

Mark jumped to his feet, pumping the air and yelling loudly enough to send Chuul’s camouflage reflex off again. He grabbed the orb, abandoning the cup of steaming hot liquid, and moved to the door.

Minxx stared after them, “Human-Mark?”

Mark only paused for a second in the doorway. He was prominently displaying his predatory teeth. Chuul had read about these “smiles” but it was still disturbing to see. “Can’t stop Minxy. I gotta let the captain know I fixed his coffee maker.”

With that, he left. Leaving Chuul and Minxx frozen in place, dumbfounded.

Wherever Chuul was going to transfer to, Minxx began to hope she could get a posting on the same ship.