Fall of Giants (The Century Trilogy, #1)

by Ken Follett

Men were the only animals that slaughtered their own kind by the million, and turned the landscape into a waste of shell craters and barbed wire. Perhaps the human race would wipe itself out completely, and leave the world to the birds and trees, Walter thought apocalyptically. Perhaps that would be for the best.

“People do things in haste, when their pride is hurt,” Mrs. Griffiths said soothingly. “ ’Specially men.”

The degradation to which you subject others comes back, sooner or later, to haunt you,