That sounds absurd to most Americans too. I've only heard that kind of rhetoric spoken by politicians, and it's definitely not a view most of us espouse.
There are a large number of Americans who believe the U.S. has the most powerful military in the world, and there are a sizeable number of Americans who believe that the U.S. provides the most opportunity for poor people to become rich through hard work (the "American dream"), but there are at least as many Americans who disagree with both, and I've never heard anyone in real life state that the U.S. is categorically "the best country in the world." Interestingly, I think it's safe to say that almost all Americans hold one view in common: no one likes the central government. That might be true in most democratic countries--I wouldn't know. But I don't think I've ever in my life heard an American state that they were satisfied with the government.