i have had two or three occasions which ended well after initiating discussions.
worth noting that on each of these occasions, there was an open window through which to talk.
there's no point in trying to respond to a driver through a closed window. just smile and wave at them if they are shouting at you, or else - more fun - cup your hand to your ear and mouth 'i can't hear you' repeatedly.
I've generally had pretty good interactions too.
"Hey, look, I just wanted to let you know", and generally they've no idea what they even did. They just seem confused, and the inevitable "But I didn't even notice you", said in a way that exonerates them completely from their actions.
"Yeah, I know, but I was there, and..."
"Alright, be safe".
I like leave it on that, me wishing them to be safe. Because that's DEEEEP.
In the US they're mad for stickers shouting about how tough they are. "26", "Share the Road", and so on. Or they just parade around with bike racks on their cars. I've pulled the old "you've got a bike rack/you're a runner/ you're whatever, you understand what I'm saying".
But sometimes cunts get lippy. Roll up their window, and then try to shunt you with their car.