1) Though I tend to take them with not so much a pinch as the entire annual output of the salt mine, stories set in an American high school in which pretty, athletic people are treated like some sort of golden demigods, and anyone else is a blundering, graceless serf. I just hate it when they have a main character who's outside the popular set, but who's desperate to break in, when the people they want to impress and to be friends with are visibly a pack of vacuous bastards. I don't want this undiscerning fuck as my protagonist, get me someone with a functioning sense of proportion, please.
Often, I'll grant you, they do make it into the it-crowd, then find out it's all hollow and meaningless, and They've Learned Something and blah blah blah. But as far as I'm concerned, if you really want to be friends with a coterie of cunts because it'll improve your social standing, then you're a pretty much a **** as well. Argueably worse, as you're not even honest about your cuntery.
2) When a story, either via dialogue or narrative, likens a romance to Romeo and Juliet. Favourably.
Hell, whenever anything quotes Shakespeare out of context and misses the point. I think the worst is "The world is [pronoun] oyster" being said as if it means "Your opportunities are limitless! Go for it!". The original line is "The world's mine oyster, which I with blade shall open!". Basically "If I want something, I'll just take it, and fuck anyone who tries to stop me."
3) When a Magical setting, artifact, individual or event is explained away with some kind of rational explaination. It was an hallucination, or elaborate trickery, or alien technology (seriously, how the fuck is that any more realistic than a wizard doing it?). I've seen it done well a few times, in a way that genuinely enhances a story (notably Mogworld), but nine times out of ten it's a jarring yank straight out of the story's arse
4) The notion of "saving Christmas". You know, fictional pillock du jour has to take over The Duty from Father Christmas, and they either breeze through it or bumble a bit but eventually get the job done. This was averted surprisingly well by Family Guy, of all things. There's also a great Doctor Who short story in which The Doctor tells Father Christmas that, due to humanity colonising outer space, Santa's Workshop eventually ends up as an ice planet covered in factories in order to keep up with the demand. The Doctor has a go being Santa. He is Not Good At It.
5) Pussyfooting around the word "Death" and its variations. "He didn't make it", and the like. A silent, grim-faced shake of the head is preferably to that pseudo-poetic horsepiss.