Could you please tell me the meaning or connotations of "warm" in these sentences from The Great Gatsby?
1) (chapter 1) I enjoyed the counter-raid so thoroughly that I came back restless. Instead of being the warm center of the world the middle-west now seemed like the ragged edge of the universe—so I decided to go east and learn the bond business.
2) (chapter 4) Little Montenegro! He lifted up the words and nodded at them—with his smile. The smile comprehended Montenegro’s troubled history and sympathized with the brave struggles of the Montenegrin people. It appreciated fully the chain of national circumstances which had elicited this tribute from Montenegro’s warm little heart.
The word "warm" seems to have different connotations in the two sentences you have quoted. As it applies to the Middle West, the word suggests friendly, folksy, kindly, cosy, familiar, comfortable, homelike, conventional, conservative, even simple and generous. It suggests the qualities embodied in so many of Norman Rockwell's paintings which appeared on the covers of the Saturday Evening Post for years.
As far as Montenegro is concerned, Nick is speaking ironically about Gatsby's patronizing smile which is ninety-nine percent false. Gatsby seems to be trying to convey the idea that he appreciates the affection which prompted the tiny little country of Montenegro to award him a medal. In this instance the word "warm" seems to suggest that Gatsby could hardly attach too much importance to a decoration from such an insignificant country but that he appreciates the gesture, the way a visiting dignitary might appreciate a bouquet presented to him by some shy little girl.
It's quite possible that Gatsby bought the Montenegrin medal in Montenegro or from some soldier he met in his European tour of duty. The whole sentence is not intended to be taken at face value. Gatsby goes to a lot of trouble to build up a legend about himself. He was a lieutenant in the army during World War I, but he might not have seen much action, and he might not have gotten any other medals. It seems as if he spent a fairly considerable part of his time at Oxford.
Anyway, the word "warm" is sarcastic. It is not used by Gatsby but by Nick, and not used to describe Montenegro but to describe Gatsby's fake, practiced smile.