Compare Lennie's death and the death of Candy's dog.

He ain’t no good to you, Candy. An’ he ain’t no good to himself. Why’n’t you shoot him, Candy?”

The old man squirmed uncomfortably. “Well—hell! I had him so long. Had him since he was a pup. I herded sheep with him.”

This was the same kind of relationship that George had with Lenny. Everyone knew, inclusung George, that Lenny wasn't good for George, that he held him back. When people questioned George as to why he kept Lenny with him, he'd say that they's been together forever, that he'd been taking care of him for a very long. time.

"From his pocket Carlson took a little leather thong. He stooped over and tied it around the old dog’s neck. All the men except Candy watched him. “Come boy. Come on, boy,” he said gently. And he said apologetically to Candy, “He won’t even feel it.” Candy did not move nor answer him. He twitched the thong.

“Come on, boy.” The old dog got slowly and stiffly to his feet and followed the gently pulling leash."

When George finds Lenny at the end of the story there's a similar scenario. Lenny waits for George exactly where he's supposed to and he trusts him. Just before George shoots Lenny, he gently coax's him to look off into the distance and envision the farm. George speaks to Lenny in the same apologetic tone that Carlson used with the dog. Lenny and the dog are both innocent, they're both doomed, and they'll both be shot by people they trust. Luckily, Candy was never put into George's position~ Carlson took care of it for him.

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