1. First, we have to talk about the theme song.
The American Horror Story theme song, composed by Charlie Clouser and Cesar Davila-Irizarry, is interesting because at the surface it's this dark, backwoods, mechanized atonal noise piece. But at the same time there's an almost jazzy Tom Waits-style bass line underneath it. It's dark and playful at the same time, which is perfect for a show with leather fetishist ghosts, aliens, Nazi scientists, and a nun possessed by the devil.
2. They took the "Kill Bill" whistle song and used it as the bone-chilling soundtrack for a school shooting.
Bernard's Herrmann's "Twisted Nerve" was used as the musical theme of a recurring flashback to a horrific massacre in the first season of the show. Just as in Kill Bill, it's both ironic and totally disturbing.
3. They made the '50s love song "Tonight You Belong to Me" by Patience And Prudence sound way more creepy than it would normally.
The show's first season begins and ends with this simple, pretty pop song. In context, its relatively lo-fi recording, high-pitched vocals, and aggressively perky tempo will make your skin crawl.
4. Mirah's "Special Death" was the theme for a doomed romance in the first season.
This incredibly sad song is used in several scenes featuring Tate and Violet, and the lyrics foreshadow their horrible fate at the end of the season.
5. "Dominque" by The Singing Nun is heard in every episode of the second season.
"Dominque" by The Singing Nun is the key song in the show's second season. It's played in every episode, specifically when a character enters a particular room of the asylum. From this point onward, the song will always be associated almost completely with the show, and Briarcliff Manor.
6. The show takes great delight in the hidden creepiness of '60s pop music.
Joe Montgomery's "Fall In Love With Me" is the soundtrack to a drunk driving hit and run accident late in season two, and it's used in a way that builds up the tension without any of the usual dynamic tricks of suspenseful horror movie music. It's all tied into the running theme that there is nothing creepier than hearing very happy music at exactly the wrong moment.
7. They also have fun with Christmas music.
Andrew Martin's "Carol of the Bells" has always been oddly foreboding for a Christmas song, and its eeriness was played up to full effect in this season's December episodes, which followed a serial killer who dresses up as Santa Claus and murders people in their houses on Christmas Eve.
8. Lastly, we need to talk about Jessica Lange's instant-classic "Name Game" scene.
Lead characters rarely go completely insane, and if they do, it's usually scored with some incredibly dramatic music. When Jessica Lange's Sister Jude goes off the deep end in episode 10 of the second season,, Murphy chose a song that didn't sound insane, but actually felt genuinely crazy. It's an ambiguous dream sequence in which Jessica Lange sings her own version of "The Name Game" and proves without a doubt to the audience that she's completely lost her damn mind, but in the very best way.