George and lennie's relationship is unusual from the rest, as they both have each other, while the rest of the raanch workers are alone. They say "we travel around together" which shows that they always have each others side. The rest of the ranch workers fidn their frienship really weird, because they have never experienced it themselves. I think that Steinbeck is trying to show that relationships were hard to build back in the 1930, hence there werent' many around.
Lennie says "i got you and you got me," which suggests that lennie is extrememly happy in having a friend. Perhaps it's because Lennie too hasn't ever experienced friendship before.
Finally, carlson says "wha the hell ya suppose is eatin them guys" which suggest thats he'll never undertsand what friendship is, as he's never experienced it before, and perhaps won't ever experience it ever in the future.
George was lennie's only hope, he relied fully on him and expected him to tell him all the instructions.
Steinbeck could be showing that relatiosnhips don't last forever, as george killed lennie in the end. Perhaps people knew this hence why they didn't try to build relationships because they knew what the outcome would be like. There's more pain in knowing and caring for someone then killing them, than just killing someone without knowing them. Carlson doesn't undertand this pain, and just continues killing.
In the end george is left alone, he's given up hope on the american dream. However Slim does get close to george which shows it's no the end, but the beginning of a new life and friendhsip. perhaps slim will understand george better than lennie as we found out during the midle of the novel, he has a better compatibility with