Cats are mysterious animals, but ones which people tend to love. Since they are so mysterious, though, a person may want to learn more about what cat's movements means. When people know this, it is easier for him or her to know what their animals are thinking at any given time. However, the main focal point for this will be their ears, as they can give you quite a bit of information. This is mainly based off of my experience with my cats.
Normal position for the cats ears are up and perky. This generally means the cat is very happy and not thinking about doing anything naughty. However, a person may also notice when the ears are up like this that the animal is sucking in noise and the ears will turn like a little radar dish toward a sound if they do not want to move their head.