A cat enjoys its own private area with all accoutrements, nice pillow, blanket, bowl and close to a fireplace. Just like people cats like their privacy so keep their litter tray in a private location, they may refuse to use it otherwise.

Cats enjoy quality foods and their meals served in the same place and at the same time each day, they are intelligent, so if you try to switch a brand label cat food for a generic label, the cat will notice and probably refuse to eat it.