I'll generally tell the clerk that I'll bag, which speeds up the lines, and I get stuff pretty much where I want it. (My store doesn't generally have a dedicated bagger)
I bring couple reusable bags, that are more like foldable boxes than a bag. It makes bagging trivial because you just set your stuff in a box. It's organizing groceries in small and fragile plastic bags that's the hard part.
I'm not sure if there's someone who will bag your groceries in all of Canada. I've always done that myself