During the wars in Iraq and Afghanistan, some American soldiers commonly listened to music in order to “motivate” themselves before action. Previous studies have shown that their most frequent choices to this effect pertained to two genres: “gangsta” rap and heavy metal. At another extreme of armed violence, Norwegian terrorist Anders Behring Breivik reported listening to a selection of tunes in the preparation of his 2011 massacre and possibly also during its perpetration. His musical choices sounded radically different from metal and rap. Yet, all of these styles of music had previously been associated with graphic violence throughout popular movies and video games. This paper asks how each type of music “worked” in motivating its listener for armed confrontation. The comparison requires going beyond the fact that mainstream media interact with common imaginaries of violence. The hypothesis here is that the differences between the terrorist’s and the soldier’s playlists reflect deeper contrasts in their engagements with the opponent. This case study of musical “motivation” leads to a broader discussion of the interplay between the agency of the listener, as opposed to the agency which he or she sometimes locates in the music itself.