A cat will drink his weight in milk, squared, just to show you he can. A cat's desire to scratch furniture is directly proportional to the cost of the furniture. A cat immersed in milk will displace her own volume, minus the amount of milk consumed. A cat's interest level will vary in inverse proportion to the amount of effort a human expends in trying to interest him. Any pill given to a cat has the potential energy to reach escape velocity.
Cats do what they want, when they want.
They rarely listen to you. They're totally unpredictable. They whine when they are not happy. When you want to play they want to be alone. When you want to be alone, they want to play.