Well, I think it’s just that every country is different, but some it most likely stems from the sense of American independence. A desire to be different, and in doing so a lot of perfectly good things changed simply because they seemed to British/European.
USA is number one:
Well, don’t you have a sense of pride in your country? Don’t you feel like there are things about your homeland that are better than others? That’s just the natural arrogance of humans, and the need to define who you are using an identifiable set of landmarks. And besides, it has a better ring to it than “USA is kind of decent!”
Slavery:
It’s not like our country is the only one that participated.
Soccer:
No idea on this one sadly, but then, I have no idea why any sports are as popular as they are.
Why do they only speak English:
Well, we don’t. You would find a large number of the population that borders Mexico to be very well spoken in Spanish. Just look at the geography of our country, it’s not like we’re surrounded by as many other nations and cultures as you find in Europe. So it’s generally unneeded for your average American.
Speaking in brand-names:
Well, what the hell are bangers and mash? Why do you call the trunk of the car the boot? Why do you go on holiday rather than vacation? It’s all a matter of where you come from. Commercialism runs rampant in the states, and a side-effect of having a brand become successful on such a massive scale is that brand name becomes the most associated with the product, so brands like Jell-o are often used to refer to just about any gelatin product.
Fear of swearing, nudity, so on:
Puritanism, old habits die hard. But just because it’s not allowed on broadcast television, radio, and the like doesn’t mean it’s not used.
Not drinking enough alcohol:
Says who?
Violence, blood, guts, gore, but no boobies:
Puritanism strikes again, and of course, we have to vent our sexual frustration somehow. Yes that was a joke, but only slightly. I think violence is accepted because we are a country founded on such, and of course nudity is evil in God’s eyes, so we can’t have any of that.
Ok, now in all seriousness, even though I tried to make my responses lighthearted, a lot of it seems to be true. I believe many of the differences stem from spite towards our lands of origin. Once we developed a nation of our very own, we began to develop a culture of our own, and that feeling still seems somewhat present. I know that doesn’t apply to every single citizen of this country, it’s just my assessment on the overall feeling. Don’t take any of it to heart; I’m not an expert by any means, so it’s all just opinion.