Have you ever hated the sound of your system one day, and loved it the next?

Last night I went to bed thinking my system was going down the tubes. This morning I loved it.
 Last night it sounded painfully bright and unbalanced.  This morning, on the same CDs, it sounded full and rich.
Now, I ask you, is it the system or me???
  I understand changes in electrical currents from the wall can play a part, but I have an expensive power conditioner.
 I was just wondering if this is a typical bugaboo among audiophiles.