In the beginning George was talking to Lennie about how his life would have been so much better if Lennie weren't around causing trouble. This shows how George made sacrifices with taking care of Lennie and stayed with him even though he caused trouble for the both of them,
"I could get along so easy and so nice if I didn’t have you on my tail. I could live so easy and maybe have a girl."
"Well, that won’t do you no good if Curley wants to plug himself up for a fighter. Just don’t have nothing to do with him. Will you remember?"
Lennie had meet Curley, who was being mean towards him and trying to start a fight, George tried defending Lennie when all of this occurred. After Curley left George told Lennie to stay away from Curley because he would only cause trouble. George shows how protective he is toward Lennie and shows how he has Lennie's back if anything happens.
"I don’t want no trouble"
At the very end of the book George shoots Lennie when he isn't paying attention to him. George did this so that Lennie won't cause no more trouble for himself and so that nobody would could hurt him. This shows that George really cares that Lennie is safe and really wanted him to be out of trouble, so that he wouldn't get hurt.
"You . . . . an’ me. Ever’body gonna be nice to you. Ain’t gonna be no more trouble. Nobody gonna hurt nobody nor steal from ‘em."