Why can't my wife just appreciate the effort that I made to surprise her?

I tried to do something nice for my wife. She was bringing her mother to visit us and to see the progress we have made on our house. I thought my wife would be happy that I put up the paneling in her room. I got the idea for the tall paneling from a catalog. I did discuss what I was planning with her. I felt crushed when I saw the look on her face when she walked inside. It was clear that she was disappointed.