Good animation is art, but that art is the byproduct of a combination of precise, deliberate techniques. And as masters of the craft, Disney films are a great showcase for how to do that.
YouTuber kaptainkristian has broken down 12 characteristic techniques from Disney films that the mega-studio leans on. Some of these techniques are pretty straightforward: a strong line of action in a character, for instance, helps establish the core expression of a character. Exaggeration is necessary to make things more identifiable for the audience. And the squash and stretch technique helps gives characters elasticity, which helps establish a sense of gravity and weight to a character's movements.
Kaptainkristian goes over all of these using clips from a range of classic Disney films. It's a great snapshot into the core underpinnings of animation, whether you're a fan of Disney films or not.
Kaptainkristian's YouTube channel has a lot of good coverage on movies and movie studios, including this look at the copyright nightmares behind Night of the Living Dead and a look at how Futurama blended humour with sci-fi.