When you love you wish to do things for. You wish to sacrifice for. You wish to serve. ~ the Priest
In the end, like the character in The Silver Linings Playbook, I wondered what was the point? Just a theory, but pointlessness may have been the point. Of all the stupid wars, WWI was one of the stupidest. Frederic and Catherine were caught up, in a war that just sort of got caught up, drawn out, and badly concluded by circumstance.
Film Rendition: Starring Gary Cooper and Helen Hayes. To be honest, I thought this was awful. Hemingway reportedly hated it as well. Skip the movie, read the book.