" The definition of superb animation is that each character on the screen makes you believe it is a thinking being. Whether it’s a T-Rex or a slinky dog or a desk lamp, if viewers sense not just movement but intention—or, put another way, emotion—then the animator has done his or her job. It’s not just lines on paper anymore; it’s a living, feeling entity. This is what I experienced that night, for the first time, as I watched Donald leap off the page. The transformation from a static line drawing to a fully dimensional, animated image was sleight of hand, nothing more, but the mystery of how it was done—not just the technical process but the way the art was imbued with such emotion—was the most interesting problem I’d ever considered. I wanted to climb through the TV screen and be part of this world. "

― Ed Catmull , Creativity, Inc.: Overcoming the Unseen Forces That Stand in the Way of True Inspiration