For many Europeans English is a second language (except for the Brits, obviously, who might ague that American English is a dialect) and they have been very much exposed to the American culture through music, movies and perhaps travel.
Therefore many European Business people assume doing business in the US is the same as at home. Although both the Unites States of America and Europe are Western cultures they operate along a very different set of values and unwritten rules. Ignore these and one will keep wondering why things did not happen your way. Do not confuse hospitality with closing a deal…
Many Europeans approach the entry onto the US market as a countrywide effort, where in reality it is a ‘continentwide’ endeavor. Doing business in the North East will be very different from closing a deal in the South, California is definitely not Massachusetts or South Carolina.
Consider this: when savvy businessmen want to do business in China they will seek local advice, find translators and hire facilitators or culture coaches, then why would all this suddenly become redundant because one speaks English?