It gives context for what is happening in the world. Reading about Chinese and Japanese history from the 19th to mid 20th century really helps with understanding why those two countries are in disagreement today. Same with the Middle East, Russia-Ukraine, and North and South Korea. It's like getting background information of a story in a video game. Without that information, everything that is happening in that story seems really confusing.

This is an answer I have given before:

So there are all these answers to this floating around as to how unlearned lessons are repeated, it lets us know where we came from, etc, etc.

I think that's crap.

Historical situations do not repeat; the details are always different. Trying to apply history at anything more than a superficial level is huntin' for a hurtin', as my friend says. You'll come to the wrong conclusions because the situations are not actually parallel. Moreover, that's not actually studying history, that's studying the present through a historical lens.

To me, and I speak as a graduate student at a T1 research university, most of the stuff that academic historians do does not possess any actual merit beyond the intellectual exercise, and even that small merit is only intelligible to other academic historians.

The true importance of historical study is its methodology, its mindset. Historical study 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.

Understanding history is important because who we are is who we were.

"History teaches us that things need not be the way they are" - Richard White

That's a legit question! Here's my take: I've had to develop business strategies, implement them, manage people and develop them, and "go to war" against competitors. None of these tasks is NEW to the world. I look back and assess how various strategies worked in various settings over history. This saves me making every mistake myself...I get to learn without stubbing my toe every time I turn around.
Second reason: the organization I work for has a structure closely resembling that of imperial Rome. It helps to know how that played out. Third reason: it helps explain the present.
Fourth: it's so danged interesting!

“If you don’t know where you came from how can you know where you’re going?” - my favourite quote on this subject.

Annoyingly, even the internet doesn't seem to know who the hell said it.

History contextualizes the world. We view events and people and places through a murky, grimy film based on our lack of knowledge, our bias, our prejudices, and our own general perceptions about what we think is really happening.

What history does is allow us to more fully understand things. To wipe away some of that grime from the window that we see the world through and hopefully gain a more complete understanding of the human experience that's happening around us all the time. We're never going to get that window perfectly clean, and we'll forever argue about what the best way to clean it is, but the point is that we try.

I tell this to my students all the time: if you care even a little bit about the people you've met and seen and talked to in your life, you owe it to them to understand a little more about them. You, me, and everyone else in the world is literally living history, so if we want to treat each other with dignity and respect then it's our responsibility to understand that history as best we can.

I'm going to try and give an analogy and hopefully that will help.

Imagine you're watching Game of Thrones. But instead of starting at season 1 episode 1 you start at season 4 episode 5. You watch all the way to the end of season 4 (no season 5 yet) and that's all you know. Are you going to really understand what's going on? Kind of, a little bit, maybe; but not really.

That's where we are. We get plopped down in the middle of an incredibly long complex TV show with no idea of what is going on. Only now there's thousands of seasons and millions of episodes and billions of characters. So in order to understand better we have to go back and figure out what happened in those earlier episodes, and who the important characters are so we aren't walking around trying to piece together everything without knowing what happened. It gives us context. Not just for how things are going but for how they may go in the future as well.

When looking closely at the present the ideas and institutions that are around now seem solid, unmovable - school was there when you were born, it was always there. And so was the government, and your town, and so on and so forth. It takes that wider view of having a story about the past to see that these things are actually much more fluid, but they tend to operate on cycles of decades or centuries in length - so you can only observe them move slightly and slowly within your lifetime.

And you can speak more honestly and freely about the past than the present, especially if nobody from the past is there to argue against you - so history has this property of being more "truthful" than media about contemporary life. Good historical arguments are logical and based on empirical evidence; they aren't guesses, lies, or attempts at popularity. Those qualities alone set historical works far apart from most media.

For me it's pretty personal. I get chills looking at something in a museum and thinking some poor schlub like me held/used/made it and for him it was part of his every day existence.

Most classes do a very poor job or conveying that the names you are studying, the deeds both great and terrible, belong to people. Ordinary human beings made up of the same meat and goo that you are.

There's a difference between knowing history and understanding history. It's easy to know facts, dates, names, etc but it's a completely different story to understand the nuances in history. History is a reflection of our own humanity and reveals our capacity for love, generosity, compassion, and our own self-destructive toward violence and war. Whether it's an engineering feat such as the the Panama Canal or the industrialization of warfare, what occurred in the past is permanent and all we can do is study and analyze the causes and effects. We can choose to ignore history or we can use history to better ourselves as a species.

My grandfather told me this once: history is important because it gives us all the lessons we need right up front. When Napoleon wanted Russia, he invaded. Unfortunately for him, the winter came and he couldn't support his army. He failed. Now what happens 150 years later in WWII? Well in case you didn't know, hitler screwed up in the same way. He invaded the Soviet Union but couldn't survive the winter and lack of resources. Hitler got within 20 miles of Moscow, but couldn't make it because he wasn't prepared enough for the winter. In all, to deny history is to ignore your mistakes from the past and hope you get it write on your own. Utter idiocy.

I was always interested in history as a child, but the way in which it was taught in my country made me loose interest it in.

So I grew up completely immersed in stories that were created by my peers or people older than me about the world. And so I kept saying these stories about my world to myself and thought of myself as belonging to this small world.

So this story of myself that I told myself - how I saw myself as I grew up - my identity was a major factor in things I would do or not do. I would choose to not be an engineer because I'd seen my father do it and it didn't appeal to me. But if I had know the history of engineering, the things that caused my father to be who he was and do what he did, I might have taken a different decision.

This is just me and the story I told myself. And this caused me to pick a different job, a different education, and create a different life.

Now multiply that but an entire family - what stories does a family tell itself? Or a village? Or a town? A city? A state? A country?

The story India tells itself about India and Pakistan is very different from the story that Pakistan tells itself about India and Pakistan. And a lot of their problems - and the problems in the lives of thousands of innocent people in Kashmir - arise from the conflict between these two stories.

On the other hand if India and Pakistan sat together and discussed their stories with facts and data and accounts from different players and formed a more objective and fact based story - a history - of themselves then their problems would be smaller, the people of Kashmir happier and life much much better for a lot of different people.

And that is why history is among the most important things you can learn.