The misuse of the word "prequel." For one thing, it's a dumb buzzword and I hate it. For another, motherfuckers use it wrong all the time.
Here's what it means: A literary, dramatic, or cinematic work whose narrative takes place before that of a preexisting work or a sequel.
The "preexisting" part is what's important to note there.
For example, The Hobbit is not a prequel to Lord of the Rings. It existed prior to Lord of the Rings being published. Those terrible Star Wars movies, however, ARE prequels since the only place they ever existed were in the very, very dark and dusty and unvisited recesses of George Lucas' brain when the original trilogy was filmed.
I realize it's dumb to get annoyed by that, and I always let it slide. And the definition of the word will likely change the more it's misused because that's how language works. But damn. So many people use it wrong.
Now it's your turn.