You're right Dave, and it's a bit childish and very unpleasant, in public and on here. But I suppose it is a case of 'Life's Little Absurdities' and the best way forward for me is to keep calm and carry on!
I usually end up in fits of giggles, but when it's a case of potential road accidents, it's not as funny. The chap didn't apologise, but stomped off grumbling to himself.