Answer:
Lennie provides constant companionship to George, someone to talk to in their lives of loneliness as migrant ranch workers.
But at the same time, the constant need to look after Lennie and prevent him from making mistakes means they have to move from one ranch to another for work. And this makes it hard to have any stability in their lives, which George deeply yarns for.
Step-by-step explanation:
John Steinbeck’s novel "Of Mice And Men," tells the story of George and Lennie and the life of migrant ranch workers. The story deals with themes of human existence, isolation, friendship, etc.
Even though Lennie may be a bit different mentally, he nevertheless provides companionship to George. As George admits, "We got somebody to talk to that gives a da mn about us. . . If them other guys gets in jail they can rot for all anybody gives a da mn. But not us." Lennie agrees, saying "I got you to look after me, and you got me to look after you, and that’s why." Lennie gives George no chance to feel lonely for he's always by his side in a world of loneliness.
But at the same time, Lennie's troublesome nature and the need to move from one place to another provide no chance for stability in their lives, which George deeply longs for. Moreover, he has to look over Lennie all the time, to make sure he is not hurt or does no wrong or else brings harm to himself or to others. This can come pretty exhausting for George.