On my way home last night I was riding on a side street, 25mph speed limit with speed humps and cars parked on both sides of the street. I was riding along around 15mph up a slight hill and a truck and car pass me as the hill crests. The down hill is pretty steep so I just take off. The truck has turned left and as I am approaching the car he puts his left turn signal on. I proceed to ride by him on the right side, between him and a parked car. As I am riding by, he blares his horn at me. I wave my hand back at him and he drives up next to me and tells me that I shouldn't pass on the right. I told him he was making a left turn and had his turn signal on, but he said that didn't matter. I was mad because it's a back road, not many people on it and he was turning left. Why should I slow down for him when he is turning off the road. I did not put him or myself in danger. I should have asked him why he passed me at the top of the hill if he knew he was turning so soon. Oh well, life goes on. I will probably encounter him again on another ride home.