Ahhh, -cracks knuckles- venting time. Some very specific things just drive me up the wall. Some of them are very subjective, others are common. Hyperbole and exaggeration incoming.
Careless grammar. Am I a jerk for judging someone fiercely if they appear to be a native speaker but canāt tell ābreathā from ābreatheā when itās a simple Google search away? Probably.
Related: Punctuation. For absolutely $0 you can press that period or comma key on your keyboard, beside the M there. Next to those is a question mark, that can be useful too, you gotta press the shift key too for it to work, though. Punctuation is completely safe to use, and gluten-free to boot. Because if you donāt use periods / Iām gonna read your entire story / Like itās beat poetry / And I donāt think thatās what you want /
Pause for a beat after every piece of dialogue. I know it might be more natural for some conversations to have a lot of pauses for thought, but this is fiction, and Iāve got stuff to do.
Long scenes without text that donāt show a lot of plot-relevant stuff. Pans that last more than 4 seconds, running scenes, etc. See reasoning above.
Drinking. I can roll my eyes past some drinking scenes. Itās a plot device, to get people to admit their deep thoughts, I get it. But itās at best a guilty pleasure, at worst a vice, if you act like itās necessary to be courageous or have a good time, I will fight you. I will absolutely not fight you. There are kids on this app, yo.
Excessive text effects in dialogue or narration. Itās a surefire way to drive me up the wall. My mental voice canāt take this change in tone. I get whiplash.
Losing points for being diplomatic or polite. Iām Canadian, being polite is my culture. Excuse you. Sorry.
Very obvious gaps in logic. Google is completely free to use. For example, I just googled when morning sickness starts, and the answer popped up right up top: 6 weeks. If your character is
the morning after, it had better be because the guy was extra stinky.
While Iām at it, pregnancy. Almost always a deal-breaker. I donāt like babies, but even if I did, a baby is a huge deal, not a plot device to move the relationship.
Cameos of the authorās friends. These had better be short and subtle. Not an entire mini-arc with a ācharacterā who doesnāt actually contribute anything to the plot.
Anachronisms. I know the outfits and backgrounds are very limited, so Iāll give yāall some leeway, but you know that horse-drawn carriages were invented before cellphones, right? Just put some thought in before you sing Beyonce in the Middle Ages without making time travel canon. Think twice before having a character say āJesus Christ!ā when Christianity isnāt canon in your story.
Excessive preaching. This aināt the place. Go vent on the forums or something yo.
-Cough- There, a pretty extensive list. 
