Dogs and cats need toys to play with otherwise they can get board and cause trouble. There are many toys you can buy for your pet and they are great for them to play with but dogs and cats need a variety of toys that they can play with. You and your pet can find toys around that house like a box.
My dog found the best toy to play with. I threw a box outside and he thought it was for him so he grabbed it and started tossing it around. He threw it up in the air and let it fall. Sometimes the box fell on him and he would grab the box and start all over. Once the box covered his head and he found it fun to be inside. In the end he ripped the box up into pieces and played with the pieces until he was tired. I had to go out and clean up the pieces but he had so much fun that it was worth it. I started giving him more boxes to play with and he enjoys them all.
Cats love boxes too especially if they live with other pets. A cat can hide in a box and that is important for them since a cat needs to have some alone time every once in awhile. Turn the box toward a wall and the cat will crawl in for some private time. It can be a sanctuary for a cat to have. Sometimes the box is a nice napping spot that can be shared with another pet. Toss some small toys into the box and it can be a small playroom for the cat where they can go to play by themselves.
A box to play with can be big enough for the pet to fit in and they can go there for private time. We all need a place to get away from it all every once in awhile.
In the case of my dog the boxes do not live forever but he has a lot of fun with his boxes. They are a cheap toy that entertains him for a long time. It can also help relieve stress and calm down a dog with anxiety. My dog is destructive with the box but he does not hurt anything else. A dog that has anxiety can benefit from having something that is okay to destroy.