I found the novels 1984 and Lord of the Flies (both required reading for school, both considered "Classics that every educated person should read" so Grimdark that I couldn't read them all the way through -- I ended up passing those classes simply because I made myself read the first sentence of every paragraph, and skimming the rest.

However, I found Albert Camus's The Plague to be uplifting, because even though nearly everyone dies, while they live, they try to support each other, and the message I took away was: "People are worth fighting for, even if it's a losing battle."