Major and minor in Metallica's One
The song has three segments: a lyric acoustic section introducing the thematic material in the a verse/chorus section, which modulates between major and minor, and a mostly instrumental section of either minor or rather monotone virtuosic rhythm-dominated martial music. The lyrics refer to Dalton Trumbo's anti-war novel Johnny Got His Gun - the video uses images from the film based on the book. They describe a soldier who has lost the ability to move and wishes only to die.
This morning I thought, damn, there are a lot of major chords in this song, esp. given it's about a guy who wants to kill himself but can't. Most of the vocal material is minor, moving into major at the end of the chorus as the soldier prays to be taken by God. The bulk of the lyrics describe the soldier's situation. So it's no great revelation but what's going on is that the major music represents the longed-for death. And no doubt one could cite similar inversions of life:death::major:minor in Mahler and Schubert and wherever.
I should note that the song does not feel at all schematic - the shifts above occur naturally and elegantly. Too many metal songs start with a lyric acoustic intro and develop according to an imposed pattern. No doubt my roommate was responding in part to "One"'s craft.