I guess we had a pretty good history teacher. She drilled into our minds that any important historical event usually had an underlying cause, a corroborating cause and a triggering cause (and often more than one of each category). So for instance on WWI, we learnt not only about Archduke Ferdinand and the Serbian "Black Hand" movement, but also about the geopolitical frictions that already existed between Austria-Hungary and Russia over the Balkan situation, etc.