Things That Drive Me Mad In Fiction, Episode 56,902:
I can't stand it when the stakes are really high, and a character makes a totally obvious rookie mistake, just because the author doesn't want to have to write an extra few pages to get them through it. Like when their enemy serves them food or drink and they hesitate, thinking it might be drugged, and the enemy says, "It's not drugged," and they just take their word for it.
Right now the one that made me put the book down for a while in sheer frustration is in Cinda Williams Chima's The Dragon Heir. The heroine has her younger brother and sister taken hostage by an evil wizard, who wants her to do something for him. He says he's stashed them someplace she'll never find if she kills him. She asks him how she's supposed to know that they're still alive and he says he's keeping them alive for leverage. And she just takes his word for it.
Of course, later they'll turn out to be still alive, because this is that kind of book, but it'll be too late for me because I've already lost my respect for her and for the author. Argh!
I also hate when there's a simple explanation that can prevent all kinds of trouble and misunderstandings and the character doesn't make it. SOOOO unrealistic. Real people spend all their time explaining; they'll shout you down to give you their explanation. We're all excuse-givers. But there's a part in the book where one of the many bad guys is trying to seduce this heroine's family by enticing the brother and sister with horseback riding. The heroine says no, they can't go horseback riding, but for some inexplicable reason, utterly fails to tell her younger siblings that the guy offering them the rides is the same one who has been causing their family serious trouble for over a year now. Instead, she just weakly gives in to their pleading. Why? There's no reason not to just tell them! There's no reason to give in on this one! It makes no sense!
In other bad news, the bad wizard puts a slave collar that only he can take off around the neck of a girl wizard, forcing her to do stuff for him. She goes into a sanctuary area, where he can't use the collar to hurt or kill her, but still does stuff for him! And she, again, utterly fails to tell anybody inside the sanctuary that the reason she's working for the bad wizard is that she has a slave collar on, even though they all know she's working for the bad guys. What the hell? Everyone knows that as long as she stays inside the sanctuary she's safe. So why wouldn't she tell them she has it on? If they help her while she's in the sanctuary, then there's nothing the bad wizard can do. Totally stupid and pointless! Argh!
Also! Everybody in this one family is magical except the mom ... SO THEY DON'T TELL HER ABOUT THE MAGIC! FOR NO REASON! UNTIL THE VERY END!
But the worst thing is that Chima invented a really interesting character in book two, who's interesting because he has strength of character, but not any strength of magic. So in book three he's useless, having no strong magic, and runs around the entire book being annoying because he feels useless. Then! Then! Chima proves to us that he's useless by killing him off! Damn! If your own creator thinks you're useless ...
Okay, wrap up to the trilogy: first book (The Warrior Heir) good, second book (The Wizard Heir) less good but more interesting, third book (The Dragon Heir) too many characters, too little common sense, a hot mess. Overall: a decent fantasy, but a little too cartoony. The bad guys are just bad. They have no real reason for being so. The magical world doesn't intersect at all with the real world in any way, even though they keep saying it does. And pretty much everybody's white. Yak.