What the US population lack in my eyes, is cultural and mental exchange with the rest of the world.
At the risk of derailing this topic yet again, I humbly submit the following as American items of culture that we have offered the world: blue jeans, Harley-Davidson (yes it is a culture more than a motorcycle, if all the t-shirts mean anything), Jazz, Blues, Rock'n Roll, Hollywood (which we may need to apologize for I admit), Pop culture icons (Superman and Spiderman anyone?), Coke and Pepsi. I could go on. As for 'mental' exchanges: the airplane, the telephone, the light bulb, the television, the electric guitar. And a little something called the Panama Canal. Both of those lists go on and on.
Lest ye think I show the exchange as one way, we do watch TGUK here, and the British film The King's Speech won our Academy Award for best picture. Examples here are harder to point out because, as Spie said, America tends to assimilate r/t differentiate.
While I agree that the Ugly American stereotype is hard to ignore, the fact is every nation gives in to that same sense of superiority, often without justification (see the upper portion of this response).
Honestly though, the worst of the three is James May, who denigrates American fast food then makes a 'pie' with Oz Clark that honestly looks just disgusting. I suppose this is why American fast food is so ubiquitous and British food vendors are so...not?
And yeah, I notice Clarkson really does like American cars, as long as they're muscle cars or 'good value for money' (the Chrysler 300 got some positive comments from him, IIRC).