I don't know about headphones, but using a cell phone in public was at one point considered rude/embarrassing: http://en.wikipedia.org/wiki/The_Finale_(Seinfeld

I don't know about headphones, but using a cell phone in public was at one point considered rude/embarrassing: http://en.wikipedia.org/wiki/The_Finale_(Seinfeld) http://en.wikipedia.org/wiki/The_Finale_(Seinfeld)