How Obstacles Help Us Perform Better
tl;dr but I did like the Ulysses S Grant story:
In 1864, Ulysses Grant fought a series of battles against Robert E. Lee in Virginia, known as the Overland Campaign. One day during this campaign, General Grant was surveying the battlefield through field glasses when a Confederate shell exploded next to him, killing a horse feet away. Grant didn't flinch. On another occasion, a steamboat in the James River exploded near Grant and his men on the shore. As Holiday writes in Obstacle,"Everyone hit the dirt, except Grant, who was seen running toward the scene of the explosion as debris and shells and even bodies rained down."
How did Grant develop this cool under such terrifying circumstances? Through a lifetime of having to shelve emotion while solving problems. When the bombs rained down on him, Grant was able to turn his heart off, so to speak, and use his head.