Ed Holland, I totally share your frustration... it's annoying how many drivers get bothered by this. It happens on one lane roads too... I pull out in to the lane and wait there with my hand sticking out for the opposing traffic to pass... and what do I get but a bunch of impatient motorists honking and swerving around me.
If I were a car turning left, I'd block the whole lane and they wouldn't even be ABLE to go around me at all!!! They should be thanking me for taking up so little space when I need to make a left turn