Many things are furry, I'm sure we would agree
But simply being furry is not all there is to be.
Here is a list of qualities a something must posess
To be not only furry, but to have true furriness.

Fur: There must be some of this; a half an inch at least, but more is preferable. The fur must also be visible at no more than second glance and at no less than five hundred inches away. While a specific color is not required, anything remotely resembling puke will not be acceptable.
Cuteness: The something being considered must be unarguably cute from at least twenty-eight and one half different angles. The one half may be accomplished either by one whole angle from which the something is halfway cute, or by an angle only halfway different from one of the twenty eight, and from which the something is entirely, unarguably cute.
Smallness: The something must fit in the palm of one's hand, and then stay there indefinitely until moved, attacked, or otherwise provoked.
Persuasiveness: The something, whether animate or no, must cause a measurable softening of feeling for anyone who looks at it for a period of a minute or longer. This may be accomplished in any way, but some techniques are more widely used than others. These include large blinking eyes, small glowing lights, and the qualities mentioned above.
Sound: In one way or another, the something must be able to produce sound. This sound must be near the top of the humanly audible range, yet must not be shrill. And most of all, not annoying. Once found to be annoying, a something is forever disqualified from furriness, and may never be considered again until a fundamental change in the state of it's matter has occurred.
The list in it's entirety could not be reproduced here, but these five qualities represent the main and most important of the tests, and so will give a fairly accurate picture of exactly what it means to have furriness.

Obviously, with such high requirements, one cannot expect many somethings to have furriness. In fact, there is only one something in the entire known world which has successfully passed the test of furriness. Unfortunately, my brother just ate it.