Had my first confrontation on Friday's commute home. It was fairly benign. I was following the rules of the road, stopped at a stop light when a guy pulls up beside me with his window down and says cycling on the road is rediculous. I politely said "it's legal". He said it didn't matter when I got hurt. That was pretty much the end of it. Most folks have been pretty decent. Some areas of Colorado are much more tolerant and used to bicycles than others. Boulder and Steamboat are extremely friendly areas to ride.