"Everything is negotiable" is a good thought to keep in mind when buying a home.

I recently wrote an offer for a buyer which specified that the refrigerator-freezer, washer, dryer and the patio furniture were included. In my experience, refrigerator-freezers usually stay with the house, but certainly not always. In this case, the seller wanted to keep the refrigerator-freezer but was happy to leave the patio furniture.
If you want the Picasso on the living room wall, ask for it.