My maternal grandfather, Harry Schneider, served in the US 1st Army during the War, having been with Gen. Pershing during his foray into Mexico after Pancho Villa. His big fight in the War was during the Meuse-Argonne offensive, where he escaped bullets but got a dose of mustard gas. He remained active in veteran's affairs and was a member of the American Legion. He passed away in December 1974.
Since I was a kid when he died, I never did get to talk to him about his war experiences. All that I knew about him I got from my mom. I did hear he tried to volunteer for reenlistment in December 1941 but got turned down. I remember having his doughboy helmet and playing soldier with it...it was just old stuff to me then.
An interesting sidenote to this was that my dad's father was a civilian translator for General Pershing's staff--he was an American but spoke French like a native and had been living in France since before the war selling farm equipment.