how did you like the end of Of Mice and Men?

I think that the ending was very interesting because it was such a twist. I didn't see it coming. When Lennie ran away because he killed Curley's wife, he actually remembered where George told him to go. Then when Curley broke into the house and said what happened, George knew what he needed to do. He went to the spot and told Lennie the story about how they were going to buy a house and live there and prosper. then he shot him in the back of the head. It was very emotional because he didn't know how to react to it. So I liked the twist but it was sad.