playlist anxiety
n. Anxiety felt by a person who fears what other people might think of the music on his or her digital music player.
Music snobs amuse themselves by laughing at a colleague's collection of showtunes, or the hopelessly pretentious jazz of the goatee-ed guy at the other end of the dorm. The flipside of this phenomenon is a new kind of fear, playlist anxiety, or worrying what other people will think of you based you your music.
—Leander Kahney, “The Cult of iPod,” Playlist, November 02, 2005
A study by Palo Alto Research Center in California released last month zooms in on the effects of 'playlistism', a form of musical voyeurism where people can scan one another's musical libraries online.

This has apparently led to what is called 'playlist anxiety'.

The researchers cite an example in which an employee was worried his co-workers might get the wrong impression because he had downloaded songs by teen idol Justin Timberlake and MOR songwriter Michael McDonald for his wife.
—Yeow Kai Chai, “You are what you listen to,” Straits Times, May 10, 2005
2005 (earliest)
"I just went through (my playlist) and said, 'I wonder what kind of image this is…giving me,'" reported one of the study's subjects. "I just went through it to see if there was stuff that would be…annoying, that I would not like people to know that I had."

The rise of playlist anxiety isn't new. The phenomenon was noted on college campuses shortly after Apple began offering the ability to stream music from other people's hard drives over local networks.
—John Borland, “Got playlist anxiety? You're not alone,” CNET News, April 06, 2005