When someone is murdered it's natural to ask why. Rarely are we astonished or perplexed when we read news reports where the motive seems to be love/hate or money/greed. And there are atrocities by madmen that we are relieved are as rare as the madmen committing them.

Then there are crimes with motives that read like absurd jokes, distracting us from their true horror. These are acts committed by people who have carried bundles of straw on their backs for too long with no way of knowing what would trigger a release of limbic rage. They often result from unwitting individuals adding that last straw, snatching that last potato chip or piece of cake at the risk of being bitten or worse.