Guys, thanks!
I have since picked up a copy of Proficient Motorcycling and started reading it on the train this morning. Glad to have it.
Mole2, I think you might be right. I was coming out of a right turn into the lane, and then another right to go into Starbucks parking lot. He was behind me from the initial rturn and more than likely was upset that I slowed him down.
I will be going to another Starbucks for a while until I get more seat time.
Thanks again!
Ken