What Makes Americans in WW1 So Different?

   I was originally going to ask a different question, but something on the class blog caught my attention to make a different comment.
    In his blogpost for this week, Lucas commented that "I was constantly catching myself judging the quoted American soldiers as twits," an experience that I could very much relate to.  This got me wondering what set this war, or these soldiers, so apart from the others?  Partly I suspect that the propagandist language one normally encounters when reading about war was so jarring this time around because we have jumped ahead from a much more morbid book covering a more morbid (at least for Americans) war: the Civil War.  Whereas the Civil War soldiers were (through the lens of Drew Gilpin Faust) much more concerned with dying, and uncertain about killing, the soldiers in Ebel's book were much more enthusiastic and optimistic about the prospect of war.
     Is it the enthusiasm that is jarring? Certainly we've dealt with propaganda and pig-headedness before (conspiracies of popery, reduction of natives to brutes), but each time this propaganda has had an uphill battle.  In Faith in the Fight the soldiers did not need the same sort of convincing, soldiers who jumped the gun and signed up before America was even at war were common sources for Ebel. 
     Perhaps this enthusiasm stems from the fact that WW1 was fought on foreign soil? I imagine that hypothesis will be tested when we read about the later wars in this course...
      What's going on here? Is this purely the work of the historians involved, and the selections of sources to serve the narrative they sought to tell? Or is there some sort of fundamental difference between this war those previous in American history?