Why do many Americans make jokes about Canada

I have a good friend who is Canadian. And I respect Canada a lot. It's one of the greatest countries in the world and everybody knows that. 

So I've actually given this question an unusual (and probably thorougly unnecessary) amount of thought : why do Americans joke about Canadians?

The conclusion I've come to is actually very simple. 

Americans find Canada funny because of one thing: to America, Canada seems like AMERICA WITHOUT THE PROBLEMS.

This is a bit confusing because I think that problems are part of the American psyche. RAcial problems, money problems, health care problems,, guns on the streets, , an old-fashioned inefficient form of government, civil liberty problems, constant wars and tears, an obesity epidemic probably greater than Canada's(as far as I know.).

AT the same time we can boast  some pretty kick-ass movies that the world flocks to see(even if they don't like to admit it; the greatest literature of the 20th century (opinion!), and our culture has been a well-spring and inspiration of musical forms  the world over for over a century; we put a man on the moon! We rule the oceans! Our big cities serve awesome cuisine from all corners of the globe!   And so on.
 Americans are dramatic by nature; we like overcoming obstacles and surviving difficult situations and enduring suffering. Our stories and literature and even history, the very mythology that shapes our national psyche is filled with startling triumphs and crushing, humiliating defeats and failures. Heroes and bad, bad villains.

 And most of the Americans I know tend to dramatize their lives and paint them in these terms.  

So to think of an America without the problems...its' just bizarre. It's like an oxymoron. The problems America has are something that actually define America and we BROADCAST THEM FAR AND WIDE FOR ALL THE WORLD TO SEE AND JUDGE. It's hard to imagine living in a society without these deep seated, seemingly unsolvable problems twisted into the fabric of said society and still be 'like America.' there's something funny about it. 

Now I know, of course, that no country is really problem-free. But most developed countries do not broadcast their problems with the vigor and enthusiasm like the USA does. So I don't know what problems Canada has. And truly caring about them...well, that would be...un-American.