Your primary and secondary education probably taught you that history is about facts, and from the very beginning you were forced to memorize facts. “The American Revolution began in 1776,” things like that. Dates, information. Everything you learned provided a simple, neat answer in factual form, with little ambiguity.
This is not history. Facts are the building blocks of history, its skeleton, but they do not give it life or purpose, because the practice of history is the practice of understanding someone who is not you. It is is an act of sympathy, of apology in the most fundamental and original meaning of both words. Correctly done, it is the full and unbiased understanding of the people of the past as they were and as they saw themselves. We are, to borrow the brilliant phrase of a terrible bigot, speakers for the dead, and our essential purpose is to cultivate a mental approach to those who are not ourselves which seeks to understand, rather than to categorize and judge. This is not the natural state of the human mind. To quote the late, great David Foster Wallace:
Think about it: there is no experience you have had that you are not the absolute centre of. The world as you experience it is there in front of YOU or behind YOU, to the left or right of YOU, on YOUR TV or YOUR monitor. And so on. Other people’s thoughts and feelings have to be communicated to you somehow, but your own are so immediate, urgent, real.
The promotion and indoctrination in a historical mode of thought is thus the indoctrination in a way of approaching the world that attempts to separate us from that basic impulse to understand the world based on our own preconceptions. Teaching this is what historians do. All that stuff with dates is just a side hobby.