Answer:
The quote shows George thinking how important his relationship with Lennie is to their lives.
Step-by-step explanation:
George and Lennie are migrant workers. This type of work establishes a very lonely life, which makes life very sad, since we all need friends to share our thoughts and experiences.
In the exception shown in the question above, George is reflecting on his friendship with Lennie. That's because even with a job that causes extreme loneliness they have a very strong friendship, which makes them very lucky and fortunate people, because they managed to establish a friendship despite the life they lead.