Best friends all over the world bicker. It's a part of being friends, and it is why people remain friends, having the ability to disagree, but stay together. The same is true in the book Of Mice and Men. Lennie and George are migrant workers that are constantly at odds, but stay together despite the knowledge that both their lives would be easier without the other. They stay together because they have been living with each other for years, and George feels a responsibility to Lennie, and because the other is simply a part of their life now. They stay together because even though their lives could be easier without each other, they know that they need each other.