The Painting I Love That Won't Sell

[Jenny A]

This is one of my personal favorites of my own work.  But it isn't a public favorite.   I still have it and just hung it over the piano..   I've sold just three prints.  Generally,  paintings are entered into shows in pairs.  One gets in or neither, but not both.  While it's mate has gotten in, this painting never has.  Am I  just enamored of it because of the technical difficulty of painting it?   Is it bad? Does it simply lack popular appeal?  Usually I know how I've gone wrong  What's wrong with this one?  Looking for serious critique, not, yes it's very nice.