Men are not blocks. People are not FTE.

If you take a flat map
And move wooden blocks upon it strategically,
The thing looks well, the blocks behave as they should.
The science of war is moving live men like blocks.
And getting the blocks into place at a fixed moment.

But it takes time to mold your men into blocks
And flat maps turn into country where creeks and gullies
Hamper your wooden squares. They stick in the brush,
They are tired and rest, they straggle after ripe blackberries,
And you cannot lift them up in your hand and move them.

–A string of blocks curling smoothly around the left
Of another string of blocks and crunching it up–

It is all so clear in the maps, so clear in the mind,
But the orders are slow, the men in the blocks are slow
To move, when they start they take too long on the way–
The General loses his stars and the block-men die

“John Brown’s Body” – Stephen Vincent Benet, most recently via the Manager-Tools newsletter.