It's pretty rare for me to encounter hostile drivers, but as it happens the last time was yesterday.
I was riding on a side street (NE 28th Avenue in Hillsboro) and there was a bit of road construction with flaggers limiting traffic to a single lane. I got stopped before the construction and when they let us through I didn't quite keep pace with the car ahead of me but I was still going about 18 mph through the construction zone. As I came out the other side and slipped into the bike lane a woman in an SUV honked and flipped me the bird as she passed.
Ordinarily I don't do well with the smile-and-wave thing, but this time her actions were just so incongruous that it genuinely made me laugh.