In this chapter, think of Curley’s wife as representative of a meaner aspect of society. At this point, most of the men have gone into town to drink and find prostitutes. The characters of Candy, Crooks, and Lennie have stayed home. They are talking and excited about the prospect of getting their own place and finally getting away from the lives they’d been living for so long.
But when Curley’s wife shows up, she is like a shot of reality. She assesses them cruelly:
They left all the weak ones here.
When Candy messes up and tells her about their plan to get their own place, she responds with:
Baloney. I seen too many of you guys. If you had two bits in the worl’ you’d be gettin’ two shots of corn with it and suckin’ the bottom of the glass. I know you guys.
Later, as she insults the men and pries at them for information, Crooks (the black stable-hand) tells her to leave. Her response is vicious:
Well, you keep your place then, nigger. I could get you strung up on a tree so easy it ain’t even funny.
The reader might feel a little pity for Curley’s wife. She is stuck in a frustrating life with an unkind husband. Her presence in this scene helps the reader see what the wider world, beyond the gates of the ranch, does to people like Candy, Lennie, and Crooks, who really are the “weak ones” in some respects.