Hemingway was driving an ambulance in Italy not because he had been injured or because he was a doctor, but because he was assisting the Red Cross on the Italian front.
Hemingway first served in World War I and later lived in Paris. He also wrote A Farewell to Arms after the war and drew on his personal experiences to do so. Finally, he retired to Key West.
Hemingway's writing style was anything but commonplace or boring. In fact, it was the lack of wordiness and the creative succintless that made Hemingway's works so popular.
The stanza in Robert Frost's 'The Road Not Taken' that most supports the theme that sometimes human beings feel conflict because they cannot have everything they desire is STANZA 1, as it's the one that speaks of the sorrow he feels for not being able to take both roads.