Can't blame the shop for the attitude, I guess, though you've certainly spent enough $ in there recently. Does the son-in law know that? Like Dave said, see the shop owner that you normally deal with. Still wouldn't expect him to be thrilled at what you did, but considering how much you have spent there, the damage might not be so bad.

At the shop I go to (most often), I know the owner pretty well. I just about never pay the price that is on the item if he rings me up. On days when he is not there, his younger assistant rings everything at exactly tag price.