Hi!
This isn't distinctly Canadian, but I thought I'd share it here. When we were at Disney several weeks ago, we ate at Hoop Dee Doo and Liberty Tree Tavern. Both are buffets served family style all you can eat dinners. That means they bring a ton of food to the table for you to share. My brother in law commented to the server that there must be alot of food wasted at these places, because we certainly left alot of food behind, not because it wasn't good, there was just so much! The server replied "That's because you're Canadians! We Americans eat a whole lot more. " And he was not joking.
Also, the same waiter caught me saying "eh" several times, though I didn't think it was a part of my language. Quite funny, it just popped out like I had no control, eh!