A friend and I were talking about this subject the other day.  We discovered that we both have days, occasionally, when we're a bit depressed or angry but don't know why.  And we both have our ways of getting to the bottom of ourselves, to lift our moods.  Of course, the other side of the coin is no problem at all.  If you're happy for any reason, known or unknown, you'll have a much better day.  Please e-mail me at:  pjones41@kc.rr.com, and come join me on facebook, too.  Farmville, anyone?