Please define

I read this term a lot here on the Gon, as well as in equipment reviews. When I think about this term, one of two possiblities comes to mind: The sound is so bad that it eventually causes ears to hurt or be fatigued?. Or, the sound lulls the listener to sleep in stead of keeping him awake by drawing him into the beautiful, dynamic music....

So, which one is it, or am I completely off base?? Help