I am cheating again. But I have to cheat: there is none out of my favourite shorts that I would pick above the others, and the entire library deserves kudos.
It always breaks my heart when animation fans, upon finding a Canadian-produced cartoon they don't like, declare all Canadian animation to be garbage and that our country should stay far away from doing it. We're just as capable as any other land mass of making great cartoons, and this oughta prove it.
In addition to the films and documentaries it's known for, The National Film Board of Canada has been producing and distributing animated shorts since 1941, in a multitude of forms, styles, and purposes.
They range from moralistic children's animation to sleek art pieces, from original stories to local folktales, and are brought to life cel, computer, and various solid materials. Television series showed these shorts to the public, while others have been broadcasted singly on public television, or released in themed video collections. Many can be found online, though not always legally.
Here are my personal favourites and their directors:
Two Sisters by Caroline Leaf
The Owl Who Married a Goose by Caroline Leaf
How Wings Are Attached to the Backs of Angels by Craig Welch
Bead Game by Ishu Patel
Paradise by Ishu Patel
Getting Started by Richard Condie
The Big Snit by Richard Condie
Why Me? by Derek Lamb and Janet Perlman
Strings by Wendy Tilby
When the Day Breaks by Amanda Forbis and Wendy Tilby
La Merle by Norm McLaren
Blankety Blank by Norm McLaren
Walking by Ryan Larkin
Street Musique by Ryan Larkin
Sleeping Betty by Claude Cloutier
The Log Driver's Waltz by John Weldon
The Sand Castle by Co Hoedman
Hunger by Peter Foldes
Mr. Frog Went A-Courtin' by Evelyn Lambert
It's impossible to choose one of these as my most favourite, because they all offer different things, and are done by different directors. Still, I'm thankful that my country's given me these options, and these fantastic shorts. I've probably even forgotten a few of my favourites, but there was the big list.