Cats identify things through their sense of smell. Even more so than by sight! Cats greet each other by touching noses. Cats also greet people by sniffing them and rubbing their scent on them to mark them as safe for future reference. Cats are comforted by the scent of their favorite people. You may find your cat sleeping on your clothes as seen in this photo above. This is because you have left traces of yourself on them and the cats recognize you by your scent.
Cats also like shoes because of the traces of where you have been on them like grass, dirt as well as other humans and animals. Many cat owners don’t understand the need to vaccinate indoor cats yearly. This is exactly why we need to. Our shoes and clothes carry all kinds of things into our house and our animals!
A cat’s sense of smell is 20X stronger than a human. Cats have scent glands on their cheeks, around their mouths, under their chins and their foreheads just below their ears. All these allow them to mark territory. Ever see your cat rubbing his face on the walls, your furniture, your leg? They are not just getting an itch, they are marking their territory to let other cats know it’s theirs!