From the Sublime to the Ridiculous

Still on the topic of war, here is some military insight mixed with gentlemanly erudition and politeness of the highest degree. From A. E. Housman:

Here dead lie we because we did not choose
  To live and shame the land from which we sprung.
Life, to be sure, is nothing much to lose;
  But young men think it is, and we were young.
If there's a poem with more wisdom condensed into four lines, I have yet to read it.