Two people get in each other’s way in a doorway. They apologise profusely: “So sorry – my fault” says one; “No, no really it was totally my fault” says the other.

The same people are driving and get in each other’s way. Behind the shield of a car, they become overwrought with rage, hurling abuse at each other, spewing foul and insulting language. They have transformed: the normally civilised person has become rabid.