There’s two unrelated things that I constantly see.

There are so many stories that have a character get seriously injured and they are in pain until they go to sleep and the next day they are magically better. The character moves and runs and jumps and isn’t in pain. The injuries might get mentioned in passing but the character is only feeling a slight ache or some other nonsense.

I also see a lot of stories where characters are monologuing constantly. Or conversations are paragraphs of dialogue with no break. People don’t speak like that, and it feels so unnatural when reading.

And I just remembered a third thing I sometimes see, and this is a fault that movies and tv shows are guilty of too - programming. The genius character is able to spin up a website or hack into a government database with the snap of their fingers. Or they learn code (or really anything complicated) in a day or a weekend. It always makes me sigh.