A very interesting topic, ewein. I remember reading an article in Scientific American many years ago, that said one of the big problems in the incompatibility of Anglos and Hispanics is that Anglos are uncomfortable to have anyone closer than three feet, and Hispanics sense hostility in anyone uncomfortable less than three feet away.
I found many sites about it, but none worth citing here. Apparently it was discussed on one of Oprah's shows.