So I had a heated conversation with a guy the other day, after he cut me up. He was being prick and at one point I suggested he was 'just another fat middle aged c*** in an Audi'.
This quite left him speechless and drew a line under the conversation.
And so my preferred refrain now to motorists in the same situation (or anyone else driving like a knob) is 'JAFMAC'
I'd love it to catch on. If you're cut up again and get into an altercation, just say 'Don't be such a JAFMAC' and watch their expression change when they ask you to explain what a JAFMAC is.