Man needs companionship and has trouble maintaining it because no humans think the same or have the exact same beliefs. To maintain a friendship you must have things in common. You must also be able to disagree with each other with a sort of understanding. Finally, you must care about that person. These three requirements to maintain a friendship are hard to keep truthfully at certain points during their lives. Some people don't have the time, concern, or the ability to carry out a flawless friendship with a companion or companions.
Lennie and George's friendship meet and go beyond all the needed requirements. They are a perfect example of loyal friends. Lennie gives George someone to talk to and someone to keep him aware and on track of things. George gives Lennie a view on the world and someone that will respect him even though he isn't as intelligent as he George. More importantly, they give each other something and someone to live for. If George wouldn't have met Lennie, he would probably be died or dying by now. If Lennie didn't meet George, he would have died soon after his aunt did, because he would either have got himself in a conflict with no one to help him or he would have simply wondered off into the world, and died of loneliness and having no companion.
Crooks suffers from lonesomeness, because he has a different color skin, but not because he is an unfriendly person. Crooks, may appear to be a mean person, but he is really just tired of being rejected and being disrespected by people around him. Crooks has a horrible life because he will most likely never have a friend that will respect him, unless he meets another black person, like himself. Crooks says, "I"ll tell ya a guy gets too lonely, he gets sick." He doesn't even have the opportunity to have a friend, and that is disappointing.
Curley's wife also suffers from lonesomeness, too. Her only companion is Curley, whom is very controlling, and he makes sure she doesn't converse with anyone other then him.