Two wise authors once said that as writers, our job is harder than God's.

In real life, no matter how unlikely anything is, if it really happens we do not question. Our credulity is not stretched to the breaking point, causing us to stop participating in the world and go looking for another one that is more convincing. Thus, God can work with the most mind-bending coincidences, far-fetched plot devices, and perverse dramatic ironies, never giving a moment's thought to whether or not his audience will buy it.

We do not have that luxury.

Ephemeral's first rule of crossovers:

"X isn't real!"
is not
"X can't be real!"
is not
"There is no X here!"
is not
"X can't be naturally occurring!"
is not
"That is not how X works!"

Always keep in mind that these are entirely separate categories of belief when you are endeavoring to shatter your character's worldview(s), and that some characters will react more strongly to some than to others, and you should know which if any is in play during any given revelation.

Ephemeral's second rule of crossovers:

If you cannot imagine a way for Taylor Hebert to win a fight, that is a fact about your imagination, not a fact about Taylor Hebert.

Things that give me a sad:

Someone ends a scene or a chapter with a character telling us, the readers, that something is "interesting" or going to get "interesting" in lieu of something interesting actually happening. I cringe every time this happens.

Someone posts a review that is not even a full sentence. It's hard to stay motivated to keep writing when this happens to me, and it annoys me on other people's stories too.

Crossovers that spend their entire first act harping on the fact that they're crossovers by pointing out inconsistencies between the two settings, when in the context of the story, the two continuities have existed in the same universe all along.

Copouts that handwave magic as having "no rational explanation" as though the setting runs on dream-logic when it obviously doesn't and the actual explanation isn't even that complicated. Especially when paired with the above.

Fics that have an interesting premise, but waste the readers time and spend the majority of their wordcount going nowhere.

Fight scenes or sex scenes (or any scenes, really) that drag on in repetitiveness, redundancy, and/or extraneous details to the point that they don't so much capture the imagination as micromanage it.

Worm fics where the author keeps getting the parahuman threat ratings wrong. Seriously, it is not that complicated. The ratings are for what the power can be used to do, not what the power is. For instance, the Thinker rating is for information-acquiring powers, not mental powers.

Use of the word "gravimetric" instead of "gravitic" to refer to things other than specifically measurements-of-gravity.

(tbc)

Stories that I will probably never write, but would love to read: (IE. Challenges)

Buffy / Lyrical Nanoha / Final Fantasy - YAHF. Buffy dresses up as Fate. Willow as Nanoha. Xander as either Yuuno or Hayate, depending. They get a shiny magic starship out of the deal, decide to go exploring... and find either Spira, Planet, or Ivalice just in time to derail the hell out of events there.

Harry Potter - AU. Young Harry is introduced to a world of magic, with one change from the way magic works in canon; one change that changes everything. Hurt? Transfigure yourself well. Ugly? Transfigure yourself pretty. Getting old? Transfigure yourself young. Poor? Transfigure some dirt into whatever you need. This is a very different wizarding world, a world without scarcity. But the difference between magical folks and muggles is that much greater, even as the ethics of hiding from the muggle world are much less ambiguous: the war is not between bigots and tolerance, it is a much fiercer and much less black-and-white conflict between those who see muggles suffering and would act as benevolent gods, and those who wish to uphold secrecy and non-interference.

FateStayNight / Pact / Worm - The holy grail war, with the FSN characters running on Pact!Magic, and Worm characters as the summoned heroes. Shirou summons Skitter? Illyia summons Lung?

rational!Buffy - The escalation would be magnificent.

Mass Effect / Game of Thrones - Shepard plus his/her love interest are somehow stranded on this mysterious artificial hollow shell world which is somehow inhabited by low-tech humans who have no knowledge of Earth, and they must unravel the truth of the origins of this shell world on the way to finding a way home.

Worm, with Taylor and Amy's powers swapped - It seems like such an obvious idea, but I've never seen a fic where this happens and Taylor ROFLstomps canon!Amy's threat level. Also, Amy Dallion the butterfly girl...

Buffy / Kingdom Hearts - Dawn gets a keyblade / Dawn is a keyblade. Because the pun had to be done and there are hijinks begging to ensue, and if I tried to write this, I'd make it serious.

Worm, for want of a Dinah - Dinah never existed. Coil never kidnapped her, thus Skitter never went spiraling into tunnel-vision-mode over her. Skitter stays with the Undersiders long-term, and gets to be her crazy awesome self, and enjoys life as a 'robber' in the so-called 'cops and robbers' game. Anti-Villain? Is that the right term?

Ranma OneHalf / ? - Instead of their canonical curses, Genma falls in the spring of drowned girl, and Ranma falls in the Spring of Drowned Tentacle Monster. Because come on why does this not already exist?! Ranma freaking out. Nodoka squeeing with inappropriate joy. Akane going catatonic. Oh my.

Worm / Frozen / Carrie /... - All those portals, all those universes with only a handful of parahumans. Elsa and Carrie (and anyone else from a "one person with weird powers" story) both get snatched up by khepri!Taylor for the final battle... and have to live with the aftermath.

Stargate SG-1 / Mass Effect - A fusion first contact. Earth opens the stargate and finds a galaxy not of goa'uld tirany but of asari, turians, salarians, and other civilizations. A SG-1 heavy direction could replace the mass relays with the stargates for a much less unified galaxy. A Mass Effect heavy direction could fudge the timeline and details a bit and replace Shepard with SG-1 as a whole. Naquadah and eezo are clearly the same thing.

The LEGO Movie / ? - A lovecraftian drama exploring the Azathoth-esque nature of The Man Upstairs and their universe. Wyldstyle finds the Piece of Resistance (or some other relic) herself, and the visions start her down a path that will test the fortitude of her mind and sanity as she glimpses the true nature of the world she lives in and tries to convince her fellow Builders of the truth before its too late. See, because if they win, that goes against the dream, and the dream ends.

Worm / Game of Thrones - The entities come to Westeros just before the King's visit to Winterfell, and parahuman's start triggering. Bran Stark triggers while falling from that window, and everything changes.

Once Upon a Tme - Emma had magic from the beginning, she just never acknowledged it. But what if she had? What if Emma had discovered her magic as a child? An Emma with a whole lot more 'superpowers' than lie-detection lives a very different life. When she finally gets to Storybrooke, she has a whole different perspective on what's going on there.