Invalid musings

I noticed it's been awhile so I'm back.  I'm a little worse for wear, having just had some surgery and being literally, laid up for a couple of weeks.  I'm looking out the window at the view of the creek and trees as I type.  It's a beautiful sunny winter's day here, I'll go out into that watery sunshine later and get some Vitamin D (I think it is).  That brings me to my question for today though - why do we always want to be active when we have to rest and vice versa?