Lennie is afraid of Curley's aggressive and pugilistic nature. He is intimidated by Curley despite the obvious difference in their sizes. Lennie has shown that he is unable to perceive his own strength before this point - George had earlier threatened to 'sock him' in order to retrieve a dead mouse, and George is considerably shorter and less muscular than Lennie.
Lennie relies on George to direct his actions when he is unsure of how to behave. He has been told to avoid Curley, but on George's instruction -'Get him, Lennie' he reaches out and clutches Curley's hand as he attempts to punch Lennie again. Lennie crushes all of the bones in Curley's hand in a defensive yet destructive gesture.
In Of Mice and Men, Lennie doesn't want to fight Curley because he's afraid he'll get in trouble with George.
Lennie isn't a fighter anyway, and never wants to cause trouble. So he isn't inclined to want to fight. But he is terrified of fighting because he thinks George won't let him tend the rabbits on their imaginary farm if he gets in trouble.
Once he does understand that George says it's okay if he does fight back, he quickly catches Curley's fist in his hand and smashes Curley's fist--fight over.
Curley's fist was swinging when Lennie reached for it. The next minute Curley was flopping like a fish on a line, and his closed fist was lost in Lennie's big hand. George ran down the room, "Leggo of him, Lennie, Let go."
By nature Lennie is not a violent man and does not seek to get into quarrels. Additionally, Lennie and Georfe are plagued by a troubled past of moving from place to place because inevitably Lennie causes physical harm to someone or something. George is constantly warning Lennie to not get them into trouble.
Lennie takes a lot of abuse from Curley before he eventually fights back, which he does after getting George’s approval. Lennie grabs Curley’s fist and crushes it. Physically, he had the potential to kill Curley relatively easily. However, Lennie typically only cuases harm accidentally.
i gt 15 points for submitting this