I don't know if it's a trope that we see in fandom so much, but it's definitely common in the source material, and it's the Breakfast Club/Beauty & the Beast, where people who wouldn't choose to be together are thrown in with one another by circumstances beyond their control, and they then have a shared understanding of the world that can't be really explained to outsiders.

Also, I have just figured out why I am so gaga for Teen Wolf, JFC.