In Steinbeck's novella filled with male characters, Curley's wife is pronounced an Eve, a temptress who disrupts the fraternity of the men.
Certainly, George perceives her as an interloper, a threat to them personally, just as the girl in Weed has been. He warns Lennie, "I never seen no piece of jail bait worse than her. You leave her be." This remark upsets Lennie, and he tells George, "I don' like this place...I wanna get outa here," unconsciously presaging the tragic events to come. Shortly after this exchange, Curley enters and asks if anyone has seen a girl. George tells him that she has been there about thirty minutes ago. Curley leaves, but because he is suspicious, he pokes his head into the bunkhouse in a few minutes, hoping to catch her coming out from a hiding spot.
Later George learns from Whit that Curley's wife often says that she is looking for him, or she thought she left something and she is looking for it.
"Seems like she can't keep away from guys. An' Curley's pants is just crawlin' with ants, but they ain't nothing come of it yet."
This news worries George more. "She's gonna make a mess." He thinks for a while, then adds,
"They's gonna be a bad mess about her. She's a jail bait all set on the trigger. That Curley got his work cut out for him. Ranch with a bunch of guy on it ain't no place for a girl, specially like her."
Clearly, Curley's wife has men on edge as they do not know "what the hell she wants" and the men are apprehensive about being too rude to her out of fear for Curley, while at the same time, they do not want to engage in any conversation with her since she may think they are interested in more than talking. Therefore, Curley's wife is a very disruptive force when she interrupts the camaraderie in the bunkhouse. She causes men to become nervous and edgy. The potential for fights is certainly a factor; indeed, Curley himself comes at Lennie, and then Lennie hurts Curley.
That Lennie would not have done anything after this is probable, but Curley's wife again reappears and the tragic events follow. Truly, she is a negative force, disruptive to the camaraderie that could develop among the men, affording them a fraternity that would enrich their lonely lives if she were not present. She antagonizes Crooks and tempts Lennie, causing him to harm her and then to lose his own life.