You know what it's like. You're sitting there quietly minding you own business when two men of a certain age start holding forth about something they obviously know nothing about. You try to ignore it: it's none of your business. But the voices get louder and louder as they become more passionate in their uninformed conviction. The first lines of 'Oliver's Army' are repeating themselves in your head:
'Don't start me talking/I could talk all night/ My mind goes sleepwalking/While I'm putting the world to right'.