“Milk bar”?
I did a Google search for “milk bar” and could not find a reference to that term being used in Canada for a convenience store. It is allegedly used in Australia, though.
“Gas bar” is rare, too. They’re usually just “Gas stations.”
Good call on “By law” though. Another Canadianism in the political realm is "riding," which is the term used for electoral districts, e.g. “Stepher Harper is the MP for the riding of Calgary Southwest.” The term comes from a Norse term.
Canadians refer to the various grades a student go to as “Grade”-Number, e.g. “Grade 7,” “Grade 4,” etc.; the usual American expression is ordinal-“grade,” e.g. "Seventh grade, “fourth grade.” Canadians refer to the four years of high school as Grade 9, Grade 10, Grade 11, and Grade 12, and years of tertiary education as first year, second year, etc.; the Americanisms “Freshman-sophomore-junior-senior” are generally unknown here. I was probably 25 years old before I even knew what order those went in, actually. Along the educational route, we also don’t generally have any terms related to fratenities or sororities because to the best of my knowledge no Canadian school has those. As God is my witness, the first time I read the term “Greek system,” I thought it was a nasty euphemism for anal sex.
Also in the educational realm, Canadians send their kids to “public schools” and, sometimes, “Separate schools,” which are public but you get the Catholic in those. “Elementary school” is used, but not nearly as commonly. Americans use “College” and “university” sort of interchangeably; in Canada, a university is a school that grants four-year and postgraduate degrees, while a college is a vocational/technical institute that grants two and three year diplomas. (The one exception, for traditional reasons, being the Royal Military College, which is in fact a university.)
“A whole whack” is a frequent Canadian colloquialism meaning “A lot of.” “Honkin’” is a modifier meaning very, usually affixed to an adjective meaning very large, e.g. “That is a honkin’ big truck.” Generally used among the younger set.
Canadians, as most veterans of the SDMB likely have noticed, refer to the country south of them as “the States,” “the U.S.” or “the USA,” almost never as “America.”
Also, with respect to the endless sub-hoagie-grinder-hero debate, I can say with confidence that both “sub” and “hoagie” are in use in Canada, inasmuch as the most popular such joint in Kingston was, of course, the Hoagie House.