On that note, Kurt Cobain's rare "Do Re Mi" demo, on the WTLO box set. It is one of the last songs recorded before his death, and while a lot folkier and more upbeat than his earlier work, it still manages to be tear inducing.
The acoustic version of "You Know You're Right" is hauntingly stark. Not that the studio version was upbeat or cheery, with lyrics like "things have never been so swell/I have never failed to feel/the pain," but the version that's just Kurt and his acoustic guitar is brutal.
Not to mention when you realize the actual lyrics go "I have never failed to fail". (If the internet is to believed)
"Pennyroyal Tea" can really be depressing (it helps if you pay attention to the lyrics knowing Kurt suffered from gastritis and drug addiction).
"Pennyroyal Tea" is also slang for a home abortion technique.
"Serve The Servants" A song about Cobain's family and childhood. William S. Burroughs, who had collaborated with Cobain, reportedly said that Cobain was already dead upon hearing the song.
"Dumb", with the subtle string arrangements and Kurt denouncing himself for feeling happy. "I think I'm dumb, or maybe just happy... I think I'm just happy..."