Medieval people viewed war as something very different. For nobility, it was an opportunity for fame and glory. For common soldiers, it was an opportunity to get rich or at least gain some wealth. For everybody involved, it was a duty and a question of honor.
One thing that seems unexplored in historical writing to me is how we use the same concept to refer to activities that have changed dramatically over the millennia.
War, specifically, is a good example: war today is a certain kind of experience, filled with bombs and drones and driving around avoiding IEDs and artillery. War a thousand years ago was an entirely different thing, where you might be fighting another guy in direct close quarters combat.
Of course it was more complex than that and you had other things like widespread disease, or boiling fat thrown at you, but it seems plausible to me that it was much easier to feel “heroic” about war in the past than in our mechanized age.