Cats don't just like small spaces, they love them. From moving boxes to grocery bags to the tiny gap between the bottom of your couch and the floor. They will even curl up in a square of tape on the floor! But why is your cat so attracted to these small spaces?
Image from rtuckernc.
The answer has to do with the security and protection that these places offer, and regardless of if they're truly safe or not, it's about how they make your cat feel. Science of Us explains how the borders of a box or corner under the couch make your cat feel comfortable, unlike sitting out in the open. When they wedge themselves into these spaces, they can relax and have an easier time keeping an eye on the limited points an attack might come from.
Besides giving your cat discarded boxes and bags to hang out in, you can make them a cat tent and make sure they have a couple of high spots they can curl up in. Higher up spots like a cat tree or shelf serve a similar purpose because they give cats a good vantage point to see any perceived threats headed their way.