This is self-explanatory, really, but these are a few things that make me want to throw a book at a wall. 1. Breaking Character This is one of the bigger ones, and it's not complicated, but is it ever easy to do, and sometimes hard to avoid. Basically, breaking character is when you have a character do something they wouldn't, and without enough apparent motivation to make it fly. Simple, yeah? Well... Character is tough. Some writers create real people (as close as they can, anyway), put them in a series of situations, and write down what happens. This makes for stronger characters, but can be hell on plotting. Other writers craft the entire story, then slot characters in to serve the plot. Upside, all of those twists and setpieces you've planned stay intact. Downside, you risk cardboard characters. Most authors seem to take a middle ground, along the lines of crafting an outline, creating a character who fits their needs, and then letting them grow and breathe while having events guide them to some extent. This is where you breaking character comes in, because sometimes, as the character becomes a person, they make decisions that don't gibe, You can try to make events guide them where you need them (risking deus ex machina), or just make them do what you want, regardless. That's laziness, but what if the author thinks the character would do something, but readers just don't buy it. That's what beta readers are for. If the majority of your betas cry bullshit, either you didn't lay out motives well enough, or there's disconnect, meaning you're going to have to go back and create a character moment or be more direct in the character-building throughout. Either one can be a bear. All of this adds up to make this a pretty common issue, but no less of a deal-breaker for readers. When this happens, we feel betrayed, and a character we may have loved before can become alien to us. Not good. 2. Homophones Another common gripe, but my inner Grammar Nazi (or Alt-Write, if you prefer) gets marching every time I see this. This is why most writers keep a dictionary in their office, and why most WP programs have a dictionary function. 3. Repetitive Descriptions Use a freaking thesaurus, people. 4. Gutting Female Characters (Not Literally) This is something I've seen a lot, and it is related to my first point. Basically, you have a strong female lead only to sideline her at the climax in favor of the male love interest because, I mean, no one's going to believe a chick could/would do that, right? This is bullshit. Ellen Ripley was created almost forty years ago, and since then we've had Sarah Connor, Leelu, Kinsey Milhone, V.I. Warshawski... The list goes on. Hell, even slasher movies know better than to do this crap. How is this still a thing? This is an abbreviated list, of course. What ticks you off?