Nothing will get you into quite such unpleasant trouble as a badly pitched joke - such is the power of humour to outrage. So it was that John Key was vilified at the Apec summit for apparently making light of the flight of the vicious child abuser and killer Philip John Smith to Chile and Brazil.
He was doing no such thing. This was humour performing one of its most important functions: helping us deal with the unpalatable, the unpleasant or the unspeakable. It is why so much humour is about sex, death and lawyers.
Here was Key in his happy place - the world stage - about to be embarrassed by meeting the leader of Chile, whither our system had allowed Smith to flee during what turned out to be a very brief escape from justice.
Asked what he would say when he met Michelle Bachelet, Key said he would warn her that someone was arriving whom "you may not want to invite round for lunch". Technically, this is the humorous strategy known as litotes or understatement, although Key, a gifted amateur in the quips game, probably wasn't aware of this.
As the Australian comic Wendy Harmer once wisely observed "Comedy isn't pretty". And although Key will probably never be offered a seat at the writers' table for The Daily Show, he does have an instinct for using humour efficiently. In this case, unfortunately, it was to protect himself, not those who needed protection.