Truth is stranger than fiction, because fiction can be stopped by editors, and lightning bolts really don't have that problem. That's why all of Zeus' myths are so ridiculous. But sometimes, even the gods of our own earthly reality bring in a hack fantasy writer to finish their work -- a coffee-stained scribbler spackling our world with the improbable adventures of Lance Thrustcock and his heroic ability to stab everything with his magical or metaphorical sword (or the spectacular science-silliness of ZERO POINT COMEDY). The dumbest fantasy tropes weren't created by dudes trying to pump out The Spell Of The Muthlrhu Elven Kings, Part 11; they were created by J.R.R. Mother Nature.
5The Royal Family Has A Sword Of Starmetal
The Shitty Fantasy:
Lance Thrustcock gripped his Thrusty Stabber, the magical weapon which had been in his family for generations. He would use it to end Vile Darkpouch's evil, which dangled over the kingdom even now. The sword was engraved with ancient, important script, but who cares about words when you can hack assholes' heads right off? Legend said it was cast from the light of the stars themselves, so hacking off assholes' heads would be drenched in heavenly glory. Bards even sang of how the Thrustcocks used it to carve out a mighty empire, but not of how the world had been at peace at the time, because it's hard to sing when someone hacks your asshole head right off.
REAL cutting critique.
The lost son of the royal family has a magical blade made of heavenly metal, a physical object embodying fantasy's shittiest core lesson: High-class people are just BETTER than all the bloody peasants. Not even because they're properly fed and more expensively trained; just because they have special shiny things while stupid farmers are too busy feeding everyone. The stories say it's the magic sword that gives our hero a chance. What it really does is tell everyone else, "Don't have a priceless antique made from space metal? Then get back to work, asshole."
The Scientific Fact
When archaeologists cracked Tutankhamun's tomb in 1925, they were astonished to find a 3,000-year-old dagger which hadn't rusted. They were even more astonished not to find it in their back after saying, "See? The curse was nonsense!" It seems Egyptian burial customs preserve weapons of war instead of protecting mummies from (well-educated) thieves. Which isn't the most subtle moral, but nothing on Earth is less subtle than a pyramid.
I - like - big - BLOCKS and I cannot lie.
X-ray fluorescence spectrometry matched the blade's metal with meteoric iron. Tutankhamun was buried with a meteorite dagger, which makes Valyrian steel look like a letter opener. Maybe that's the only thing that can kill mummies. It also demonstrates the biggest problem with fantasy weapons: If there is a priceless relic weapon, in reality, the fabulously rich ruler of the totalitarian kingdom is much more likely own it.
4Time Warps Between Different Regions
The Shitty Fantasy:
Lance Thrustcock had formerly been standing in a stormy winter, the sky cursed by the dangling evil of Vile Darkpouch, but this new land was bright, innocent, and summery. It was almost as if the time ran differently here, and as if the writer couldn't think of a subtler way of suggesting this. He'd been whisked here by incredibly long-lived and wise women who were still mega-hot, wore bottle caps and thin leather straps for armor, and inexplicably wanted to get it on with Lance, even though by their standards, he must have been a particularly stupid two-year-old. And if we can have a magical land where time runs differently, well, we can definitely ignore how a thug like Lance wouldn't have worked out time dilation in a million years.
Unlike his time-travelling descendant, Lance Timecock.
Time running differently in a magical land is a mythical cliche. Dicking around with time is also a great way of pretending that exposition is part of the story. Why subtly imply how things ended up this way if you can go right back and tell everyone! It also reveals the "world" as a disconnected series of things for Lance to lance, because even one functioning time-differential mechanism would utterly reshape society beyond anything like the usual swords-and-orcs bullshit.
The Scientific Fact
The most stupidly impossible of all science fiction or fantasy tropes is a core component of our reality. General relativity means that all mass is leaning on the fast-forward and slow motion buttons, depending on where you're standing, quite literally all the time. You've probably read about it happening near light speed or awesome events like black holes. But it's also happening right under your feet.
You might even find a time when these shoes are a good idea.
Time is moving more slowly underground. Massive time dilation means the Earth's core is 2.5 years younger than the surface. The sun's core is 40,000 years younger than its surface, and since it takes light 100,000 years to escape that core, that means every bit of solar energy has traveled through time and relative dimensions in space. It's the Universe's final, desperate attempt to end jokes about nerds needing to go outside.
Of course, we can't actually go down to the center of the Earth and check. Because even in an article about fantasy magic and Doctor Who, The Core was hilariously nonsensical bullshit.
"I know a bunch of science words, and now I will write a script about ALL of them."