Because some couch makers put cat food in the couches..... just kidding i dunno
Mostly, no. Cats just like/need to scratch things, and they might scratch your couches if you don't give them a proper scratching post(by proper, i mean tall enough and stable; scratching, in cats' minds, is stretching :P). If your cat keeps scratching the couch anyway, you can put double-sided tape on the couch. Cats don't like sticky surfaces. Also, you can train cats to not jump on the stove or something and knock over a pot.
Cats scratch mirrors to mark their territory, stretch their muscles, and maintain their claws.
Cats scratch windows to mark their territory, stretch their muscles, and sharpen their claws.
Cats scratch on mirrors to mark their territory, stretch their muscles, and maintain their claws. Mirrors may also provide a reflective surface that intrigues cats, leading them to scratch.
Cats may scratch on glass surfaces out of curiosity, to mark their territory, or to sharpen their claws.
Cats scratch on windows to mark their territory, stretch their muscles, and communicate their needs or desires.
Cats will scratch at just about anything, sometimes it's the leather furniture.
YES! Their claws, a natural defense, WILL SCRATCH SOFT SURFACES.
Cats scratch as a natural behavior to mark their territory and keep their claws healthy. They don't scratch to intentionally hurt you, but it can be painful if they scratch you accidentally. Cats may not feel bad about scratching you, as it is instinctual for them.
dogs + cats = scratch scratch scratch
Cats scratch blankets to mark their territory, stretch their muscles, and keep their claws healthy and sharp.
Cats scratch glass surfaces to mark their territory, stretch their muscles, and sharpen their claws.