" Guys like us, that work on ranches are the loneliest guys in the world."
So the quote fits right in as how George and Lennie are different from the other ranchers. They have something to look forward to and keep going having a future unlike the others.
Curley comes off aggressive and rude a little bit to George and Lennie as he picks a pick mostly with Lennie. Since he's the boss's son he holds his held high as he can't be touched or anything unlike George and Lennie even though he picks a fight with Lennie more as he hates dealing with the big guys. The good advice George gives Lennie is to basically to stay out of Curely's way no matter what which is trying to keep him of out of trouble as a good thing .
Even though all these characters talk big most of them stand alone / are lonely at heart. For instance, George is one of them as he uses Lennie as his company and that's his drive through this journey; keeping out of trouble represents his care for him and their undeniable good friendship. No matter how many times he says how good it would be alone he'd truly rather have Lennie by his side as in why he keeps Lennie with him through everything he put him through. As the other character Candy, in this case doesn't want to put his dog down because he's already feel alone and will feel more lonely as the dog is the only family Candy really has anymore and putting that dog down even with the offer of new ones it wouldn't feel the same. All George has to do is keep Lennie around and better the friendship. They have then he won't feel lonely and Candy needs to get a new friend to get close with so the pain can at least semi go away.
Credits:
Created with images by CircaSassy - "The Story of the cat and the mouse ([between 1855 and 1858])"