1. It's (generally) cleaner and nicer there. It's a stereotype, but it's true. Montreal looks like a theme park without a theme. Toronto looks like what New York was supposed to look like in 2000 in an early 1960's SF novel, plus streetcars and (some) interesting Art Deco survivals. Now and then, you'll see something close to American squalor, but not much. Somehow, there's a kind of Cordwainer Smith vibe going on, a clockwork world just out of touch with time...Every panel of sidewalk in Toronto has the year it was laid stamped into it. Walk in Toronto, hopscotch through the years.
2. Pretty much everyone's Scotch (scots, scottish...), the way almost every third person in the Northeast is Irish. (Then, there's that French thing...) This takes some getting used to. Although they speak ordinary English mostly, now and then you'll find someone with an obvious burr. This can be very startling, especially since no one else seems to notice but you. (The same goes for kilts.) The other is that, unlike Irish, there are different types and degrees of burr, ranging from the Shrek-like to the liltingly charming to the Shrek-like and charming. Also, Scots are, how shall I put it? different. They think faster, are slightly more emotionally volatile, and have a skewwy sense of humor. It's not necessarily bad, just different. Some people say they're standoffish, or cold, or prudish. They are, but they're also warm, raunchy, and friendly. You just have to catch the same person at the right time. As for the French, what can I say? They're there. They're French. No one seems to get over it.
3. It's a whole different universe up there. Again, SF. Remember all those alternate-universe novels where the world was just a little different? Canada is like that. Brand names are one clue. Everyone's heard of Molson's, but what are you to make of a billboard with people drinking beer where the only print visible is a large "OV"? Or the fact that there are a lot more candy stores (of the old-fashioned Fannie Farmer type) with a picture of a house, and the lavish lettering reads "Laura Secord"? It obviously looks like a piece of well-known history, but.... when?...and ...where??
You get change in Monopoly money. You can pick up nickles with a magnet. Everything is a third more expensive, but again, no one seems to mind it. There still exist fur shops. No, wait! Not even like that. I mean Fur. Shops. as in there are piles of pelts lying there, and old geezers going in to turn them in, saying "I tried to deal with the Bay, and..." You wonder whether he was trying to buy a blanket, or whiskey. Or...does it matter? People drink tea, sometimes. No, not posing young folks and antioxidant minders, but old biddies, normal people. And all kinds of women play Bingo, and almost all of them knit. Shockingly, no one seems to notice this either.
I mentioned the streetcars in Toronto. They're red and white and gold, and look like huge expensive toys. Pretty much everything in Toronto that's official is red and white and gold, with touches of black. It's actually kind of exciting-looking, a punctuation mark of the four primal colors of Man. Remember, you're in the British Commonwealth here. This means...an awful lot. Think of what would have happened if George Washington lost. Or, if you're anything near a history buff, the War of 1812. You're living in that world, here.
If you crave a little cheap romance in your life, you can shop at a Boots for, well, anything you'd buy in a drugstore. Yuppers. Same chain that you used to read about Londoners picking up a few jacks of smack in, only, there's no smack, but great perfume instead. (The store brand wins awards, regularly.)
4. Prepare for small indignities, and great pleasures. OK,they don't have Italian. Or, better identifiable Italian. Too bad. But what about that affordable French place? Or that really great pub? And that record store with the techno stuff and neat comix in French? (But they eat french fries with cheese and gravy here...ugh) You find you can't live without that underground bazaar (they wouldn't, couldn't allow it in the States) with the HUGE waterbed and real Hindu kohl. Userfriendly is a newspaper comic here, not an Internet abberation.
5. Smile, and get with the program. Isn't it great to be an expat? Don't you just want to live there? Or at least, count the days until you can be here again? Suuuureeeeee......