I agree with most of the replies. In my years of riding, mostly in the deep south where rednecks abound, 99%+ of drivers, including the rednecks, simply want to pass you and will do so when it is safe for you and them. The problems I've seen often involve groups of riders that are difficult to pass safely. That tends to really p.o. drivers, with some reason. Sometimes cyclists are their own worst enemy. Frankly, my main concern is less with the guy who is out to harass cyclists and more with the inattentive driver talking on a cellphone or, god forbid, trying to text, while approaching me.
Unfortunately, it only takes one idiot to cause you serious injury or harm. That can occur anywhere and anytime, here or abroad. Don't worry about riding in the US. But when you come over use a mirror, pay attention, avoid riding at night when possible and high traffic court roads and wave to the motorists who are looking out for you most of the time. You will have a great time and meet great people.