Purring is one of those magical cat mysteries - no one reallyknows why or how...I've read that some will purr when upset AND when happy - perhaps it's a "fail safe" mechanism, like when we "whistle in the dark" to pretend not to be afraid

The tail thing is fascinating. Ritz's tail whips around when she is excited or upset, but also has a very distinctive "wave" when we call her name. Calling "Ritz" will 99% of the time, unless she is otherwise occupied with a mousie or very sound asleep, will instigate a single left to right tail sweep.