Simple Score of Sadness

A soundtrack can be very useful for setting the scene. The style of music tells you what the mood's going to be, and awesome moments need booming soundtracks with lots of instruments making up the sound to be even more awesome.

But with depressing moments, it's the other way around: you only need a slow and soft melody with very few instruments to know that what's happening or has just happened is supposed to be a Tear Jerker - if not for the audience, then for the characters at least.

Subtropes include Nostalgic Music Box, Lonely Piano Piece, Playing the Heart Strings and One-Woman Wail.

Anime and Manga

 * Naruto has lots of these, including the appropriately titled 'Sadness and Sorrow' from the original series, and 'Despair', 'Tragic' and 'Loneliness' from Naruto Shippuden.
 * Puella Magi Madoka Magica has the theme of Sayaka, Decretum,
 * This unnamed song from Yu Yu Hakusho.
 * Queen's Blade has one at the end of Episode 7 of the 2nd season, where Tomoe kills Shizuka.
 * Bleach has Will of the Heart.

Film - Animated

 * "Sally's Song" from The Nightmare Before Christmas is noticeably softer and simpler than the rest of the movie's soundtrack. In the song, Sally talks about how she's afraid Jack will never notice how she feels about him.

Film - Live Action

 * Used in Return of the Jedi, when Darth Vader Anakin Skywalker dies in front of his son Luke.
 * The movie of Harry Potter and the Sorcerer's Stone uses this when.
 * This was used quite ham-handedly in The Girl in Gold Boots, where Critter would break into overly sad ballads every time it was necessary to tug the audience's heartstrings. This is parodied in one of the Mystery Science Theater 3000 host segments, where Mike strums a guitar in the same style.
 * Most of the songs in the Heisei Godzilla films are upbeat or sound like they're best suited for action/suspense scenes. And, then you have the far more somber "Requiem" which plays at the end of Godzilla vs. Destoroyah while.
 * The soundtrack to Moon. The main theme is rather fast-paced (though still simplistic), but it slows down for the main dramatic moments.
 * Any of the versions of the Rohan theme in the film of The Two Towers that are stated on solo hardanger fiddle.

Live Action TV

 * In a show that wasn't afraid to break out the electric guitar for fight scenes, it's worth noting that Buffy and Angel's love theme pretty much always sounds like this.
 * The Incredible Hulk's "The Lonely Man" closing theme - piano solo.

Video Games

 * "Moon" and "Fortitude" from Umineko no Naku Koro Ni.
 * Likewise, a simple piano solo from "Rush" in Dreamfall when.
 * "At The Bottom Of Night" from Chrono Trigger is a rather simple piece for the amount of emotion it evokes.
 * "Theme of Sadness" from the first Suikoden game.
 * Also there is an ensemble version of this song.
 * "Requiem" from Alundra is also a good example.
 * The exact same song was also used in Legend of Legaia, as Cara's Theme.
 * "Midna's Desperate Hour" from The Legend of Zelda Twilight Princess.
 * The music for "Abandoned Ebon Keep" in Secret of Evermore.
 * Disgaea - an entire game full of peppy, upbeat songs... and then there's "Sorrowful Angel".
 * "Painful Memories" from Heavy Rain.
 * "Heartbeats" by Broove in the newgrounds game "Colour your World" and other works by Silverstitch.
 * "15 years ago" that plays during the nuclear explosion flashback and the quiet drama scene in the last mission of Ace Combat 5.
 * "Homesickness" from Tsukihime.
 * Fond Memories from Secret of Mana. The description for the video says it all.
 * Ezio's Family from Assassin's Creed II probably counts.
 * Enclosure and The Best Is Yet To come from Metal Gear Solid.
 * The Eight Melodies, Smile and Tears and ESPECIALLY the Theme of Love from the MOTHER series.
 * Emotion and  from Pokémon Black and White.
 * Mass Effect 3 brings us I Was Lost Without You (at least for the first part of the song, which is also the game's love theme, it builds up towards the climax).
 * As well as Leaving Earth, which has a sad piano tune backed by a bass section doing a convincing imitation of the Reaper Horn. The song is played in the beginning of the game
 * And of course, An End Once And For All, which is a reprise of both Leaving Earth and the Normandy theme.

Western Animation

 * Avatar: The Last Airbender:
 * The song that plays when.
 * Iroh's song  in 'Tales of Ba Sing Se'.
 * Also, the music playing during the final Agni Kai between . There is just something so final about the score, probably because it's only slowly beating drums and string instruments playing a series of chords. It's oddly fitting for this action scene in Sozin's Comet. Definitely a Tear Jerker, especially since it follows this exchange: