A ringing in the ears. It's normally temporary, but it can be permanent. People who frequent loud concerts and/or people who listen to their MP3 players at full blast (with headphones, of course) are the main victims of Tinnitus.
Random Teenager: Damn, why did I have to listen to my music so loud? I wish I had just turned down the volume. How am I supposed to sleep with this Tinnitus?
Hym Iam "I have tinnitus all the time now. Trying to sleep? Tinnitus. Wake up? Tinnitus. Right now? Tinnitus. It's all the fucking time and I'm seriously starting to get pissed off about it. The tinnitus. The popping sound. The pain. And you wonder why I want to kill."