I understand that people might have trouble in their day-to-day lives. What i don’t understand is how someone could watch Colin Firth and Geoffrey Rush engage with one another onscreen for almost two hours and think that their accents sound exactly alike.
Geoffrey Rush, the actor playing the speech therapist, IS Australian, and sounds Australian, and played that role as an Australian. Brits and Aussies will not agree with your assessment that he sounds like his English co-stars in that movie.
A generic Canadian accent and a generic US accent are pretty darn similar, and I’d expect indistinguishable for many, if not most, North Americans. So it’s not just you. It’s nowhere near the difference between accents like Received Pronunciation UK English and Australian or South African or things of that nature. But there are some Canadian accents that are unmistakably not USA-ian (like in the Maritime provinces), although I suspect a lot of Americans wouldn’t identify them as Canadian, either–more likely lopping them with Irish, Scottish, or Northern English.
The USA has been settled by Europeans for 400-500 years, Australia 150-200. There have been telecommunications of some sort in both places for around 100 years, meaning the USA had 300-400 years to develop distinct regional accents, Australia only 50-100.
There are minor regional variations between states; the word “Newcastle” is pronounced in Queensland as “new-cassle” and elsewhere as “new-carsle” for instance. Similarly “basic” is “bassick” in Qld and “base-ick” elsewhere.
People from Adelaide say"advarnce" whereas most others say “advaance” - similarly with “darnce” vs “daance” and so on.
But no, there are not what I would call big variations.
Variations in vocabulary are a bigger clue to region in Australia than variations in accent.
I think if you mixed together an Australian, South African, and New Zealand accent, you’d get something like this.
I think he’s lost or muddied his Aus accent, he sounds like he’s been in New Zealand or South Africa for an extended period of time.
I do wonder what my accent sounds like these days, after thirteen years living in Australia. I reckon I have NZ pronunciation, but Australian conformity with some vowel sounds.
I’m an American and I don’t agree that he sounded British. His accent was *clearly *Australian to me.
(I also immediately thought “Manchester” when watching the video **snailboy **posted, so maybe I’m just better at recognizing accents than the typical American.)
+1
Pack up your port, and head up my way and I’ll shout you a By Jingo (eh) 
I immediately perceived it as East side of Manchester - Oldham, maybe Stockport - I have friends who come from that area, so I’ve got a datum for comparison.
The further away an English accent from our own (that is further in terms of our everyday experience, which loosely correlates with further away geographically), the more likely we are to lump it together with all the others.
I’m constantly amazed by people saying ‘the British accent’, and meaning not just RP, but meaning that they can’t tell the difference between a Yorkshireman, a Scouser and a Londoner, but it’s just that the perception of similarity and difference in accents is something that humans just don’t do very objectively - that which is familiar to us is finely divided, everything else is lumped.
Glossop. But pretty close. For those unfamiliar with the area, we are talking a matter of about ten miles here.
So close!
There really is no major general difference between a Canadian accent and an American accent. There are certainly regional accents in one country that have no similar accent in the other, but then there are others that do. The general television accents are pretty much identical. Even we can’t tell them apart so don’t worry about that.
John Clarke sounding extraordinarily Australian, I must say…
Good program, but!
I was watching Masterchef: Australia this morning and could hear distinct differences between the accents. Not that I’d have been able to say where each person came from, but they were different.
OK We seem to get a lot of Canadians who take some offence at being taken for Americans, and I had assumed that there was some element of “surely you can tell the difference” much as we had discussed the Australian versus English accents.
He is becoming a bit of a national treasure isn’t he? 
I was going to post a link to a clip with him as an example of what we would call perfect Aussie. His dry sense of humour is something we all love. A bit past its prime, but this was done during the BP Gulf of Mexico spill. As an additional exercise, contrast the accent of the presenter in the first few seconds, to that of John and Brian in the subsequent sketch.
On the subject of it being difficult to tell, one problem is that it is easy to change (or adjust in a context) one’s (Australian) accent. In my case, at least while I was on the Eastern seaboard, I pronounced more words with a short “a” than I did before I moved there. So maybe fresh on arrival you could tell, but the longer I lived there, the harder it would become.
I’ve noticed that in the US, the subtle differences in Canandian speech mostly disappear. But the accent of the Quebecers makes them unintelligible. Almost like they’re speaking a different language
I’m still astonished that there aren’t regional accents in Australia. I can pick out the differing accents of people who live only a few miles from me here in the US.
I can pick up on many Canadian accents immediately. On Battlestar Galactica, I knew right away that Colonel Tigh was Canadian. However, a lot of Canadian actors don’t have Canadian accents, like William Shatner.
Yeah, Michael Hogan has pretty much the prototypical Canadian accent. Another actor that I use as having a rather noticeable accent is Wendy Crewson, who played Harrison Ford’s wife in Air Force One. When she had her big emotion line of “He will NOT negotiate!” I was thinking, “Which country are you first lady of again?”
Canadian accents seem to vary more in strength than in actual “quality”, leaving aside the Maritimes, Newfoundland, Quebec and the North. There’s pockets of variation here and there and some vocab differences, but for the most part it’s a pretty consistent landmass of accent, with the particular quirks just being stronger or weaker in some people.
The T-Mobile girl, Carly Foulkes (You Tube clip with audio) is another one that has what I would term a fairly discernable Canadian accent, although I’ve discovered it seems that not everyone hears it. You only have to listen up to 0:25.