Not American, but my views of America being "the good guy" completely crumbled when I read Chomsky's Manufacturing Consent.
It made me put into perspective the amount of propaganda we're being fed by mass media, just by reporting with carefully chosen words. It's obviously not limited to America, because the same patterns are being used all around the world to justify imperialism, nationalism and ruthless capitalism.
It also helped me realise how fucked up some of the things my government did (and is still doing to be fair) and we just gobble it up, because it's insanely hard to get out of the bubbles we've created for ourselves.
For anyone looking to get some of those views right away (as opposed to reading an entire book), here's a short (<10min) video of Chomsky talking about propaganda terms in the media and what they mean.
I live in France, and roughly 90% of the media is between the hands of a dozen people at most. You can really feel the impact in the general population.
I woke up after Powell's speech to the UN, accusing Iraq of having WMD. He didn't present any real evidence, but every TV show and almost every newspaper said it was an "Open and Shut" case over and over. One guy even wrote "only a fool or a Frenchman would doubt now",