Hecklers. Those gloriously irreverant types who like the sound of their own voices so much that that they feel everyone should listen to them.
Heckling is traditional in politics, was common in Music Halls, is expected at football matches (although no one can hear you anyway) and has strangely died down in modern times - probably since recording devices maximised possible embarassment and since the internet began offering a much safer and anonymous means of complaining loudly about public figures.
Yesterday The Independent's Pandora reported that former Australian prime minister John Howard had been heckled and had a pair of shoes thrown at him during a speech at the Cambridge Union, in an obvious copy of the Iranian journalist who chucked his shoes at the then US president George Bush.
Perhaps because modern politeness has made heckling scarcer there are a few instances which have gained notoriety - and they are not confined to politics, as comedians and musicians will tell you.
We've picked ten of the most infamous heckles of the last couple of decades and some of the pretty explosive responses they've garnered.