I died in hell. They called it Passchendaele. - Siegfried Sassoon

I must add that in the light of subsequent events it is difficult to believe that a Peace negotiated in 1917 would have been permanent. I share the general opinion that nothing on earth would have prevented a recurrence of Teutonic aggressiveness.

You smug-faced crowds with kindling eye Who cheer when soldier lads march by, Sneak home and pray you’ll never know The hell where youth and laughter go.

One evening I asked whether he [Rivers] thought I was suffering from shell-shock.
‘Certainly not,’ he replied.
'What have I got then?’
'Well, you appear to be suffering from an anti-war complex.