Curley's wife finds Candy, Lennie and Crooks in Crooks's room on a night when the other men, including her husband, have all gone into town to a whorehouse. On seeing the three together, she observes that 'They left all the weak ones here' (Chapter 4). When they, like all the other men (except maybe Slim) refuse to talk to her she flies into a rage, labeling them as
a bunch of bindle stiffs – a nigger and a dum-dum and a lousy old sheep (chapter 4)
The three men are all socially marginalized – Crooks on account of his colour, Lennie because of his mental slowness and Candy as he is old and disabled, and Curley’s wife use this fact against them in her anger. She is especially cruel to Crooks, threatening to get him lynched, and when Candy retaliates, she remarks scornfully that ‘No-body’d listen to you,’ (chapter 4) and Candy has to admit she's right.
Candy, Crooks and Lennie are easy targets for abuse and exclusion due to their perceived differences. However, Curley’s wife mocking them for this is rather ironic as really she is the most isolated one of all at the ranch, due to her gender. She is young and lonely; her husband is an unpleasant man who has no time for her and the other men are wary of her, thinking that she is simply out to try and seduce them when all she is seeking is someone to talk to. She shows that she is not really mean at heart when she talks easily with Lennie in the barn; it is really frustration at her loneliness that causes her to lash out.
With Lennie, for a brief space, Curley’s wife finally gets the companionship she so craves; but tragically, Lennie, in his sheer uncomprehending brute strength, goes on to cause her death.