In The Great Gatsby, Nick leaves New York and heads back west in disgust. Jaded by his experiences with Gatsby, the Buchanans, Jordan Baker, etc.,...

I think Nick will remain cynical when he returns home to the Midwest.  After all, he left the Midwest because he'd already become rather disillusioned with it.  In Chapter I, Nick says that he came back from the war "restless" and with a sense that

"Instead of being the warm center of the world, the Middle West now seemed like the ragged edge of the universe [...]." 

Therefore, it seems unlikely that Nick would be satisfied moving back to the place that he wasn't happy in before.  Before, he was cynical about the place, and now he's cynical about people, so it doesn't seem like there's much possibility that Nick would feel any better about anything when he gets back home.  By the end of the story, Nick understands that there is little to be optimistic about.  He says,

"Gatsby believed in the green light, the orgastic future that year by year recedes before us.  It eluded us then, but that's no matter -- to-morrow we will run faster, stretch out our arms farther . . . . And one fine morning--."  

Nick now understands that this fine morning will never come. The dream in which Gatsby believed is only a dream and will never be reality.