I got sprayed by a water bottle today from a girl in a passing RV. She yelled some things at me, but I could'nt tell what she said. It just sounded like some crazy yelling/laughing/screaming. I agree, the best reaction is to not react. Definitely don't want to provoke someone further. It's a downer, but at the same time I probably saw somewhere around 50 other cyclists and motorists today that gave a friendly wave. Don't let one bad one spoil your day.