Brian Armstrong prefers to be a wartime CEO: “I used to think that I was better as a peacetime CEO, but I think that's not true. It's actually totally flipped.” “I think it's wartime, all the time.” “And I actually realized that I like wartime.” “I find it very energizing and motivating. It can make you really pissed in certain moments too, but it's actually very energizing. And sometimes when there isn't any conflict or war going on, I get a little bored and tired and I'm just like—it…