The first class I had to take when I did my MA in history was on historiography. One of the guys in our class made the statement that whatever the most recent work on a subject became the "truth", as the author had the last word. We called him "Truth" from then on. Of course, he was completely wrong.
The problem of really understanding history, the truth, is that you don't always know the motivations of the participants, and history is a participatory exercise. As Alan Clark wrote in his seminal work, Barboarossa, "What were Hitler's private convictions, which he turned over in his mind, in the darkness of his bedroom, concerning the state of war and the prospects of the Reich?"
Without necessarily understanding the reasons for a decisions, the actual history is hard to explain.
While this may seem self-evident, in a great deal of history and in news reporting, which is a form of history, this is often hardly explained. Much of the work is superficial, trying to explain in sweeping terms events that turned on the most mundane matters.