I love: twist endings.
Sometimes referred to as O. Henry endings, for the pen name of William Sidney Porter, a writer who specialized in them, twist endings happen when something completely unexpected throws a curve ball at the characters.
Clumsy foreshadowing will completely ruin a twist ending. If you can see it coming, it wasn’t a twist. But if the foreshadowing is actually really subtle, you only see it after the twist has been revealed, in which case you say “OH I SHOULD HAVE SEEN THAT!!!”
Sticking some stupid crap reveal where there is no precedent for it also ruins a twist ending. You see it a lot in horror films. Happy Birthday to Me has a good example.
The most famous of O. Henry’s twisty stories is The Gift of the Magi, where if you don’t know what happens, then you didn’t pay attention in school. You can read it at the link. It’s not long.
Movies with good twist endings are The Sixth Sense, The Mist, Planet of the Apes (1968), and Psycho. Literary works with good twist endings are Shutter Island (I haven’t read it, only saw the movie, but it’s a great one), Stephen King’s The Dark Tower series (you have to read seven fat-ass books to get there, but it’s worth it), and Guy de Maupassant’s short story The Necklace.
I hate: tropes.
The word trope has more than one meaning. First, rhetorical figurative language that twists one word or phrase away from its literal meaning.
In time, it came to refer to devices, characters and elements that are peculiar to certain genre types and recur within them. They’re not always clichés just yet, but identifying which genre they belong to is really easy.
I don’t hate them exactly. Unfortunately, they’ve all been used in so many combinations that it’s very difficult to come up with something fresh. New combinations are tough to find.
There’s a wiki called TV Tropes that details many of the tropes in film, books, television, and the like. Read it with caution. If you’re a writer, it’ll make you hyper-aware of overused tropes in your own work, which will either help you or make you feel like crap!
Either way, it’s a very entertaining site. A few tropes have attained legendary status. Woe to you if you use them in anything less than a deliberate manner.
The Mary Sue character
This is a character that is so incredibly wonderful in every way that she is completely unbelievable. Piss all over Mary Sue; she’ll come up with a lip-trembling, magnanimous reason why you should be forgiven.
Please, please, please, make it stop. The only way I can even stand this is when both twins are evil.
Why do villains have to explain everything to the hero? Is he/she so dumb as to not figure it out after expending great effort to stop whatever the villain is doing? Batman never asks for an explanation. He knows what is going on. Although, sometimes it’s really hard to make Joker shut the hell up.
Many writers, especially in TV and films, use it as a stalling device so a rescuer can get there in time or the hero can come up with a way out.
A misunderstanding without any discussion
What is this, Three’s Company? Most people, if they don’t understand something, will at least say, “Huh?” thus inviting some kind of explanation. I can’t stand it when characters don’t ask.
Be creative; think up a really good reason why they can’t get the information they need. Maybe even make their worst suspicions come true and go from there. It’ll ramp up the conflict. If it looks like a duck, walks like a duck and quacks like one, it ain’t a pony.
Men are stupid, or women are too emotional
Let’s skip the generalization, please. Your characters should have some individuality. Not all women are emotional, cry at the drop of a hat, throw things when they’re on the rag, etc. And not all men are dimwits who can’t even iron a shirt.
You can avoid eye-rolling among your readers if you take the time to develop well-rounded characters, with believable motivations. Try mixing up a few tropes and see if you can’t come up with something new.