Introducing a second cat. I botched the initial introduction, and my older cat was constantly angry and stressed! She would barely let us touch her, and the cats fought fairly often. I was able to reintroduce my new cat, and they are now pals! My older cat snuggles with me again and is generally more relaxed. They can help solve so many problems with simple solutions! It amazed me how such small changes (specific types of toys, for example) can improve your and your cats quality of life.