A further example of understatement comes from Nick Carraway right at the start of the book. Here, he describes his experiences of serving in the army during World War I:

I graduated from New Haven in 1915, just a quarter of a century after my father, and a little later I participated in that delayed Teutonic migration known as the Great War. I enjoyed the counter-raid so thoroughly that I came back restless.

Let's take a moment to reflect on just how casual this statement is. Nick participated in what at that time was the bloodiest conflict in human history, yet he talks about it as if it were just a minor episode in his life. And when he returns to American soil after the war, he doesn't describe himself as being shocked, disillusioned, or traumatized—he says he is merely "restless."

One gets the impression that Nick was able to move on from the war in a way that just wasn't possible for millions of others. The whole culture of the 1920s—the culture of the so-called Lost Generation—was profoundly shaped by World War I. Yet Nick doesn't appear to have been affected in the same way as his contemporaries. It is this marked degree of separation from those around him that enables Nick to be such a faithful observer and which, in turn, makes him such an excellent narrator.

In the opening chapter of the book, Nick, the narrator, describes where he lives on Long Island, and specifically, West Egg.  He calls it "less fashionable" than East Egg and in doing so is using understatement since East Egg is very glamorous and populated by some very rich people.  West Egg, too, has its very rich people (Gatsby, for example).  Then when Nick gets to the Buchanan's house, Tom comments that he has "...a nice place here" when he lives in an extravagant mansion.  Most of the descriptions that Nick gives us are detailed and accurate, and he uses more irony than he does understatement, but in describing the wealth and extravagance of both the Buchanans and Gatsby, there is some understatement.  Both the Buchanans and Gatsby spend great amounts of money - the Buchanans because they are used to it and Gatsby because he wants to impress people, especially Daisy. Nick gives Gatsby's parties a vivid accounting of the elaborateness, but he holds back a little on other aspects of Gatsby's surroundings.  In chapter 2, when Nick is describing Myrtle, he uses some understatement when he tells about how she changes (both literally in changing her clothes and figuratively in changing her persona) once she gets in the car with Tom and they go to the apartment in the city.  Myrtle puts on airs as easily as she puts on new clothes. Nick is subtle in this description using understatement.