What were the social causes of World War 1?

In many of the countries involved in WW1 there was serious industrial unrest in the years before 1914 and some historians think this may have been one reason (among many) for some governments to welcome war a distraction, as something to make everyone rally round the flag. I think this view is worth noting but that it should be treated with caution as an explanation for the outbreak of war in 1914.