Since I'm on a roll with sharing some of my older short stories, here is the second-shortest one I ever published, weighing it at right around 500 words. It was published on a website called From The Asylum and then reprinted in their Tales From The Asylum: Year 3 anthology. Fair warning -- it's a groaner...
Professor Maass flung the machine against the wall. “Enough,” he roared. “I quit! I quit, I quit, I quit!”
“But professor...” his assistant said, watching pieces of shattered electronics skitter across the room like luminous cockroaches, “you’ve proven that time travel is possible, at least theoretically. You can’t give up on building a working time machine now. You just can’t.”
“No, Oliver” replied Maass, shaking his head. “It’s just not meant to be. As if the whole project were cursed from the day I conceived it.”
Oliver’s eyes grew as wide and white as ping-pong balls. “I’ve spent twenty-five years working on this project -– devoted my entire career to you. Because I believed in you.” He took a step toward the professor. “You can’t do this to me -- ”
The professor pivoted away from Oliver and gesticulated wildly at the giant blackboard behind them. “Look, damn you. Look! Every time I think we’ve got the calculations right, we find a pair of numbers transposed, or an exponential notation off by a single digit.”
Suddenly sullen, Professor Maass knelt among the ruins of his time machine, picking up a tiny fragment. He cradled it like a clump of dirt he was about to throw into a freshly dug grave. “Every time I think we’ve got the wiring right, some connection works itself loose, or a chip goes in upside-down, or the laser’s lens gets a smudge on it.
“No, time travel may be theoretically possible, but it’s not practical. Mankind is just not capable of getting that many fine details perfectly aligned.”
The professor clenched his fist around the broken piece of his dream, squeezing it until it cut his palm. Blood dripped from his hand.
Ever so softly, he said, “I quit.”
“But -- ”
Screaming, Professor Maass turned on his assistant. “Didn’t you hear me?!” he howled. His bloody fist, still clutching the broken piece of hardware, pummeled Oliver’s head and shoulders. “I said it’s over. Over! Done!”
The professor’s screaming and pounding continued relentlessly, until the blood wasn’t just coming from his cut hand anymore, it was coming from his assistant’s face and neck and scalp.
“Done, done, done...”
* * *
“You see,” said the first Timeguardian, pointing to the holographic display of Professor Maass’s breakdown. “This is why we had to intervene. They’re just not ready to handle time travel yet.”
"Too violent?" asked the second Guardian.
"Good grief, no," replied the first. "If you'd been jerked around for twenty-five years by people from the future, you'd have a breakdown and beat the hell out of somebody, too. The problem is that they’re technologically advanced enough, but don’t pay sufficient attention. You can't allow people to hop around the time continuum if they're not paying attention, and after all of this time, Maass really should have figured out what we were doing to him and his equipment…”