There are two significant statements that Nick makes in the novel that, according to him, define his character and make him different. The first is in chapter one where he declares:
"I’m inclined to reserve all judgments..."
It is therefore painfully ironic that we find, however, that throughout the novel Nick does make unreserved judgments. When he, for example, describes Tom Buchanan, he uses phrases such as, "Tom would drift on forever seeking", "Two shining arrogant eyes", "gave him the appearance of always leaning aggressively forward", "a cruel body", " ... the impression of fractiousness he conveyed. There was a touch of paternal contempt in it."
In a similar vein, he describes Daisy Buchanan, Jordan Baker, the guests at Jay Gatsby's parties, Jay Gatsby himself, etc. It is in chapter eight, however, that Nick's so-called "reserved judgment" is not so reserved after all, when he shouts to Jay:
“They’re a rotten crowd,” “You’re worth the whole damn bunch put together.”
"I am one of the few honest people that I have ever known."
The remark comes across not only as high-handed and facetious, but also judgmental and self virtuous, for throughout the novel, Nick does a number of things which cannot possibly be deemed "honest." Firstly, he starts a relationship with Jordan Baker, knowing full well that he is still involved in a relationship back home, an affair he describes as, "that tangle back home." He conveniently dismisses this relationship by saying:
"Nevertheless there was a vague understanding that had to be tactfully broken off before I was free."
But he does not break off the relationship, opting to go along with what he has with Miss Baker.
Furthermore, Nick prefers to remain silent about Tom's affair with Myrtle Wilson. He does not confront Tom about it and neither does he inform Daisy. He also does not say anything about Daisy being responsible for Myrtle Wilson's death. Once again, he prefers keeping mum.
This is the true irony.