In "Of Mice and Men," what does Slim mean when he says "a guy got to sometimes"?
When Slim says "A guy got to sometimes," right at the end of the book, he's referring to George shooting Lennie. He's saying not that a man has to shoot another man sometime—that rarely happens—but that a man sometimes has to step up and do the difficult thing. This is foreshadowed earlier in the book when he nudges Carlson along in killing his old dog. It's a recognition of responsibility, and of how hard it is to do the ethical thing sometimes. He's trying to consol George in a difficult time.