When one has a strong passion for something they will do anything to make it possible.
"I remember about the rabbits" (4)
"The hell with the rabbits. That's all you ever remember is them rabbits" (5)
When one fears they will lose their passion for their dream, they will repeat it over and over to keep it clear in their mind.
"An live off the fatta lan" (56)
"Tell about that place, George" (56)
Determination and persistence is the key to achieving something important. If ones drive is so strong, they will sacrifice anything to achieve it.
"They fell into a silence. They looked at one another, amazed. This thing they had never really believed in was coming true." (60)
Lennie is a very forgetful person while George is not and has a more of an elaborate interpretation of the dream. Lennie knows exactly what he wants and he is persistent about making it happen while George has a more realistic mindset for their dream.
Lennie enjoys listening to George explain his dream creating a clear image in Lennie's mind keeping him excited. Both Lennie and George want to remember their dream so they do not lose hope and achieving it.
George especially got excited when he realized Candy's money might make the farm dream a reality. It seems as though the money is the difference between the dream and the success. Now both George and Lennie feel that their unrealistic ideal is becoming a realistic reality.