Earphoned music is the mortal equivalent of the super-power of invisibilty.
The difference is that instead of actually disappearing, you simply feel as though you have. Instantaneously, the world around you shrinks a little. Things feel further away. People don't notice you (as much). When you cant hear yourself moving, walking, coughing, typing....you start to feel like others cant either.
Also, the louder the music, or, the more squishy and earplug-like the earphone, the greater the invisibility.