Why do cats flick their tails?

Cats flick their tails slowly and in an upright position when they are content. However, if they begin to quickly thrash their tail or twitch their tail in a lower position then they are most likely upset and irritated by something.

Cats also dilate their pupils and flatten their ears when they are upset. If a cat is giving this signal, it is a sign that all humans and animals should leave the cat alone. When cats are upset, they tend to like to stew in their annoyance by themselves. They often retreat to a favorite piece of furniture and stay there. When human owners go over to the cat and try to engage it, they may be scratched or hissed at.