My friend--I hesitate to use the word friend, since I have only met her once and talked via email a few times, but acquaintance just doesn't sound good--my friend over at Texas in Africa had a blog post recently about going to Africa for the first time. It's worth reading just for the the fun (she's usually very funny) and for the application for any trip out of the US.
It doesn't matter where Americans go, we're bound to be the most arrogant people there. Even Christians. Maybe especially Christians. See TIA points #4, 5, 19, 23, and 35. My wife and I went to Paris (France, not Texas) for our 10th anniversary. People always ask if we saw any arrogant people in France. We did, but virtually all of them were Americans. Same in South America.
The truth is that everyone is proud of where they're from. And they should be. But Americans seem to have a unique way of displaying that pride in a way that puts down every other culture. It really only shows how small we can be.
So go here and read TIA's 38 points for going to Africa for the first time. It's worth it.