Dogs are an easy read - they're the kind of friend you don't have to worry about offending. But cats, oh cats.
Mysterious, inscrutable and liable to be pissed off at the drop of a hat, yet somehow all is forgiven with a flick of the tail, a soft purr and big, round Puss-In-Boots eyes.
This video from Cats Communication explains brilliantly what your cat is trying to communicate - they use a mixture of their tail, fur and teeth to display their emotions.
The voiceover says that when lying on their bellies, they are "communicating trust and comfort" while when aggressive, their tail hair is erect, the back legs stiffened and ears are pulled back.
Ears can tell you a lot about your cat. When relaxed they feel calm, when erect they are focussed and paying attention to what's going on. Flat ears mean they are feeling defensive.
Tails - like most animals - also convey their emotions. Vertical tails mean they are happy and when they are relaxed, it swings from side to side.