My husband is a serial road rager. He rages within 1 minute of driving. I tell him to stop raging over something you can't control.
One day he was driving and got annoyed at a merging car. At the next set of lights my husband pulled up next to him, rolled down his window and had a go a him. Cue me, sliding down my seat, embarassed at this childish exchange.
Next minute the other driver says 'I don't know what the road rules are where your from'. Oh.no.he.didn't.
No need to cross that line, mate. Road rage still not acceptable in my books though.