I am sitting in the library working on a term paper.
I have my headphones plugged into my computer and am listening to Chris Cagle's My Life is a Country Song at medium blast.
I can't hear anything around me because my headphones are sound canceling.
I have been working for twenty minutes and nobody has acted at all abnormally.
My friend from statistics walks up behind me and motions to take out my headphones. She wants to tell me something.
I remove the headphones and note that I can still hear the music. My computer speakers are blaring the music even though my headphones are plugged in!
I look around the library at the ten or fifteen students gathered in my study area. None of them return my looks.