After I had my cat spayed, she underwent a personality change. Before she was skittish. Loud noises would send her running from the room to hide for hours. Now, she thinks nothing of them.

The cardboard box I can understand. Only my cat has issues with any paper product. It will die a slow and painful death from her sharp claws. One drawback to teaching your cats to stay off the counters: mice. At the other house, we had a mouse that decided to move in with us. The cat would sit in the floor and stare at the mouse as it ran along the counters, but would not get up there.