Lot's of things annoy me.
Here's another thread on the topic.
Probably the thing that annoys me the most is repetition or redundancy of any kind:
- Redundant phrases like "nodded his head," "blinked her eyes," and "shrugged his shoulders"
- Scenes that are very similar to previous scenes (repetition of effect)
- Same words or phrases being used over and over
- Every character reacting to everything with a facial expression or small gesture, especially when they all use the same expressions and gestures (everyone rolling their eyes at everything, everyone sighing all the time, everyone "quirking" an eyebrow)
Beyond these, here are some other annoyances:
Main character Too Stupid To Live (TSTL) -- the plot is based around the character's idiotic, immature decisions yet it's not a slapstick comedy about an idiotic, immature dweeb. In other words, don't tell me the main character is smart, then have her make really stupid decisions to move the plot.
Main character is too perfect (a Mary Sue). Nothing is ever her fault. All of her problems stem from people being unnecessarily mean to her, because they are just plain mean, or because they are jealous of her beauty/talent etc.
Stakes too low or nonexistent. What will happen to the main character if he fails to attain his goals? If the answer is anything from "not much" to "nothing, really" I can't be bothered.
Quite the opposite of that last one, stakes that are too large in scale bug me too. I hate high concept
save the world/save the universe/save mankind/save faerie-kind types of stories, but that's just me. I like a relatable story, and when the stakes are enormous and all encompassing, I can't relate.