Ian, I know EXACTLY what you are talking about from firsthand experience.
Was on my way home from work (about a month or two ago) and this dhead in a small blue charade-type car was annoying me, so I gave him the finger. BIG mistake - this guy must have been on drugs or something because the way he overreacted was frightening.
He pulled in front of me, slowed right down trying to bait me to move lanes, but I stood my ground. To cut a long story short, he through scrunched up card at me. The first bit hit the bike and the second time was when he was pissed that I wouldn't go in the lane beside him, so he swerved suddenly to get alongside me and threw more - this time it hit me in the chest and apar from being dangerous - it hurt.
The whole time I refused to look at him and this annoyed him even more. I managed to escape (long story) and rode to a cop station near home to report him. I was shaking so much i could barely ride. Let's just say that if this guy had pulled out a handgun, I wouldn't have been surprised.
To my great annoyance, as soon as I started to tell the duty cop my story, I completely forgot the driver's rego that I had been memorising and chanting to keep me sane on my journey to the station.
As you can tell from this long post (sorry!), the whole thing really freaked me out and shook my confidence for a few days afterwards.
