Can't say I've experienced that phenomenon, but then I've only got music playing at certain times....
Mood
Last night, listening before I went to bed, I was convinced there was something radically wrong with my system. Nothing sounded good. This morning I decided to play something I was sure would sound good. All of a sudden my mood picked up. Now everything I heard after that was reference sound quality.
I wonder if anyone else has had that kind of mood swing from one day to the next.