In Black Adder the general is planning an attack, carefully lays his toy soldiers out neatly, then chuckles and literally gets a broom to sweep them away. He's utterly indifferent to the slaughter he's ordering, and takes a perverse joy in finding the men who thought they'd tucked themselves away in "safe" jobs and personally ordering them into the lines, to their deaths.
In the meantime, army commanders I've actually met are haunted by their choices. The most traumatized airmen I've known was haunted by the responsiblity of giving aircraft permission to fly, even though he always made the right call and none of his ever went down.
Were WW1 commanders truly indifferent to the men they ordered to their deaths, or is the Black Adder interpretation a fiction?
The Black Adder series was actually reflecting a belief common for some time, especially in Britain in the 1960's, that the officers in WWI had little concern for their soldiers' lives, sending them "over the top" to die, and were stubbornly attached to ancient strategy and tactics. It was well articulated in Alan Clark's The Donkeys, and even put on stage and in film in Oh! What a Lovely War!. It was, however, not really true. First, there had been a very long convention of officers being brave in the face of enemy fire, and that resulted in a very high death and injury rate among officers at the front: they were dying along with their men. Second, though Clark made a lot of such fossils as Sir John French, the British generals actually did change, try new things: tanks, mines, creeping artillery barrages, poison gas. They tried to more and more meticulously plan attacks- Herbert Plumer was especially noted for this. They got better at logistics- supplying the front, and supplying soldiers who'd taken enemy ground.
As far as agonizing, though: they were professionals. They were given the job of fighting a war by the political leaders above them, and they fought it. And if a campaign resulted in thousands of deaths, those political leaders never told the generals the cost was too high and they were to stop fighting. So, they kept fighting the war- and had to accept the high cost. After the war was over, though, there were indeed a lot of officers scarred- Robert Graves' Goodbye to All That is a good memoir that shows it. Douglas Haig, who had overall command of British forces, spent the remaining ten years of his life after the War to fundraising and campaigning for benefits for ex-servicemen, difficult for someone who disliked making speeches. Like medical care on the front, it was something of a forlorn hope compared to the immense damage that had been done. But at least you can say that he didn't simply abandon them and retire to his country home.