When this quote was said, Nick was really drunk and thinking about the aliveness feeling of the city but its something which he wants to feel once but not all the time because he thinks that city is fun and everything but not a place to spend all the time or to live; its just something he likes once in a blue moon. Nick ton of this wasn’t clam or relaxing it was way more then that because he was pretty drunk when he was think of this. He had negative view and positive view. When he was thinking, Tom punches this guy because that guy was calling his wife name many times. It was juxtaposition for Nick because he was thinking of something which cant be even compared or anything. So what he thought and what he saw had no relation. What he saw after what thought of the aliveness and bad things of the city was very dramatic for him.