As for the guy pulling out to block, I think it's a reaction to the flashing. Flashing your lights is supposed to be a "Hey, I'm here" thing. For most of the public it has become "Move the **** out of the way, asshole!" Europeans understand the flash-to-pass thing. They actually have to demostrate competence to get a license. Most Ammuricuns take it personally.
He was reacting to being called an asshole. Not flashing the lights would have given a clean pass with no reaction. Betcha money. Soon's we find that time machine so we can go back and try it.
(The competence thing is not intended to be a political rant, just a statement of general behavioral differences while driving, them vs. us.)