Do you ever start a story, then come across something that makes you stop reading? I’ve done this many times. 
Here are some questions:
An interesting and unique plot, characters with a real personality and personality development.
Probably bad grammar and poor vocabulary. It annoys me but it’s necessary a reason for me to actually stop reading.
Lot of cliches, boring plot or characters.
I rather have very plain than bad directing, but it’s not something that necessarily makes me exit a story right away but it has to be a good story besides that to keep me interested!
Unique plots and characters 
Bad grammar or a typo
Characters with no character development
Boring plot twists…
“ShE is NoT LiKe The OtHeR GiRLS” 
When two characters develop romantic feelings for each other for no reason although I chose a thriller/mystery story to avoid romance… 
Back when I read episode, I didn’t mind bad directing as long as it was still understandable what’s happening in the story and as long as I didn’t get a headache from it 
Bad directing if you are talking episode story wise. If not, then if the first few chapters don’t catch my attention, then that would make me stop reading.
Characters I can relate to, an interesting plot that leaves me excited for the next chapter, a good sense of humor, and great dialogue that feels natural; not forced.
Directing errors that aren’t that serious, a few spelling/grammar errors in an otherwise well-written story, or when I’m too invested in the story to stop reading, even though there was a plot twist I didn’t like or the main characters start acting annoying. If I’m really invested in the story, I’ll probably keep reading unless…
Very explicit sex scenes, graphic violence, excessive swearing or graphic language, too many unnecessary filler scenes, a disappointing plot twist where the characters start acting out-of-character… or if they kill off a very beloved character.
Only if I don’t like the story or characters enough, and the directing is so bad it makes the story unreadable.
Bump
I like reading stories with a good plot, interesting characters, sometimes romance and things like that. Supernatural stories are good too. The plot has to be well written though. The characters need to have depth to their personalities.
It depends on if the poorly directed, severe grammar problems and if the characters do not have the necessary depth to them. I understand if you speak another language but if you speak english as your main language then I have a problem with your bad grammar. Don’t be surprised if I say something in the feedback section. I rarely have to do this to people.
I already have a problem with not finishing some stories I read so this is mixed issue for me. Most of the time when I see severe grammar problems in a story with more reads then 100 I will stop reading in the first episode unless I feel like it could just be accidental. Like that 200 plus Vampire story on Episode. I dropped that one as soon as I saw how many reads and the bad grammar problems in the first couple of episodes. Certain stories deter me from reading them if they go over major abuse, glorify suicide, and they do not portray mental illness correctly. As someone with family members who have endured all three of those problems it makes me sensitive to reading them. Really bad directing like the whole episode has to be bad.
People can make mistakes with directing which does happen but if you have over a 100 something reads and you still haven’t fixed the errors in your story then yeah I stop reading. Since that means you do not take the time to go back to fix anything wrong or improve certain scenes. I test my story multiple times in a row to make sure I don’t miss anything but sometimes a small error will slip through. Doesn’t mean I won’t leave it there. Fix your mistakes because people do read your stories and they will see them. It’s kind of hard now to not go through a story nitpicking about directing and grammar issues since I’m a writer as well. Don’t use text language in text dialogue boxes unless you are using a phone screen background. Not everyone knows that language very well and it looks unprofessional in a story if used incorrectly.
Anyone recently experienced something that made you stop reading the book or story?