Purring can be difficult to read . . . it can signify contentment as well as discomfort. I watched a TV program all about cats and it mentioned that cats never purr when alone . . . they had a microphone in a room with a person and a purring cat, and as soon as the person left the room, the purring ceased.

I've heard that hissing at your cat as a means of discipline works wonders . . . it is a language they can understand from when they were kittens and disobeyed mom!