Paintings held hostage

I have worked with several galleries is my time and one of the hardest things for me to get my head around is why every once in awhile one wants to hold my ' paintings hostage'.

Blue skies, 12x12', oil and cold wax on panel, $395

By that I mean the artist goes into business in good faith, contracts are signed and off we go!  The gallery wants good art and we want sales.  But lets say the sales don't come?  Well the artist wants the paintings back but the gallery says no, you can not break the contract and the art stays. So there are still no sales and the artist is caught between a rock and a hard place. We wait the contract out........