This is just my ramblings some of this was taught in school some of this is from Canadian veterans and some is from history books.
Canada and Australia were major players in WW2 in their respective theatres of war. Canada in the Atlantic and European theatre and Australia in the pacific and it is very unfortunate that they often get only passing mention in many history books.
While the US and Britain could field huge military units and switch them out of the front lines for rest and recovery frequently neither Canada or Australia had that luxury and often their military units in all branches would spend weeks and months at the front lines resulting in heavy losses and minimal replacements whereas both the Americans and British could replace entire divisions if needed.
The side effect of being on the front lines so often was that both Canada and Australia had very experienced and effective fighting units that their enemies feared whether it be in the air, sea or land. Unfortunately both the Americans and British had negative views of the losses both their smaller counterparts incurred and often were stated as much in dispatches especially by less experienced US and British commanders.
In the Atlantic the Canadian Navy was the backbone of the convoy system and it resulted in the Canadian navy becoming one of the best navies for anti submarine warfare during and the decades following WW2. Many history books mention in detail the British and American navies but give passing mention to the Canadian navy and their important and vital contribution to the war.
In both Canada and Australia I believe something like 85% of all personnel served in active duty combat whereas the US I read that less than 40% of their military served in active combat with the British being around 60-70% serving in active combat. The Germans in Italy and Europe quickly came to respect and fear the Canadians with many German officers stating after the war that they would often upon seeing Canadian uniforms or seeing Canadian troops they knew they were in for a fight and sometimes even retreated rather than face the Canucks as a German general put it during the Italian campaign “if we saw the Canadians we knew we were in for a fight we would rather fight the British or Americans than face the Canadians”
In the pacific the Australians were known as tenacious fighters and small units were known to hold off entire Japanese divisions. I am less familiar with the Australian military but one American Commander was stated as saying “give me an Australian regiment over an American division any day” that says a lot right there.