The humor that comes from The Onion is rooted in the fact that an element of truth is at the basis of all its stories.
But sometimes, the stories are 100% true, and written in honest language without the need of exaggeration or parody. Sometimes, they're dead-on. And these are the articles I think are the most well-written from The Onion; they're simultaneously funny and sad.
Like these two environmentally-themed articles: