"Cats are not interested in pleasing anyone by a display of obedience. They are unfailingly pragmatic, which in itself seems to denote a kind of intelligence we are not yet equipped to measure. If a cat can detect no self-advantage in what it is being told to do, it says the hell with it, and, if pressure is brought to bear, it will grow increasingly surly and irritable to the point where it is hopeless to continue. Yet, where the advantage to be gained is clearly related to the task required, the learning process is so acute as to be almost instantaneous. Once learned the feat will be repeated only when the cat is interested in the result."
--- from The House Guests (1965)