Compare the presentation of Tybalt in Romeo and Juliet and Curley in Of Mice and Men, and what it reveals about their masculinity.

Shakespeare's Tybalt and Steinbeck's Curley represent the most negative aspects of masculinity. Both men are bullies and hold a good deal of power. Tybalt is from the wealthy Capulet family and so influences the men around him. Curley is the boss's son and has authority over the workers at the ranch. Both men wield their power with arrogance and violence. They both tend to act before thinking, as they are quick to enter into fights without listening to reason.

Tybalt appears in three scenes in Romeo and Juliet. In each scene his anger and belligerence are his most prominent characteristics. In Act I, Scene 1 he further instigates the violence which the Capulet servants have already started. He won't listen to the more level-headed Benvolio and instead insults him and threatens to kill him:

What, art thou drawn among these heartless hinds?
Turn thee, Benvolio; look upon thy death.

In Act I, Scene 5 he is again angered beyond reason as he overhears Romeo at Capulet's party. He immediately calls for his sword and is out to prompt a fight with Romeo when he is intercepted by Lord Capulet who doesn't want his party spoiled. In fact, Capulet, until his outburst in Act III, Scene 5, seems to represent the best aspects of masculinity. He is judicious, calm and shows humility. He is protective of his daughter, and when Tybalt attempts to spoil the party, he even speaks well of Romeo, saying,

Verona brags of him
To be a virtuous and well-governed youth.

Eventually Tybalt backs down to his uncle, but vows to seek revenge later. He tends to hold a grudge and is not able to move beyond a perceived insult. In Act III, Scene 1 he ignores Romeo's pleas of restraint and, since Romeo won't fight, he engages Mercutio, who is equally childish in his display of masculinity. Neither man can accept what they perceive as weakness. That both men are killed reveals Shakespeare's verdict on men who are deaf to reason and display the worst characteristics of masculinity.

Like Tybalt, Curley has a quick temper. Steinbeck describes him as a braggart (everyone knows about how he competed in the Golden Gloves) and "pugnacious" (quick to fight). In chapter three, Candy perfectly describes Curley as a bully:

“Never did seem right to me. S’pose Curley jumps a big guy an’ licks him. Ever’body says what a game guy Curley is. And s’pose he does the same thing and gets licked. Then ever’body says the big guy oughtta pick somebody his own size, and maybe they gang up on the big guy. Never did seem right to me. Seems like Curley ain’t givin’ nobody a chance.” 

Curley's interactions with the men on the ranch are tense and seem to be always verging on violence. When he first meets George and Lennie, Steinbeck writes that "his hands closed into fists." Curley basically orders Lennie to talk with him and George has to warn Lennie to stay away from Curley. Steinbeck juxtaposes Curley with Slim, who represents a better example of masculinity. Slim is not judgmental, remains calm in the face of chaos and is well respected by the other men. Steinbeck writes that because everybody believed in Slim his decisions on any matter were carried through.

Curley is the direct opposite of Slim. The men disrespect him behind his back and even to his face after he accuses Slim of being with his wife in chapter three. This only proves to enrage Curley as he lashes out at Lennie, who is smiling over the thought of the farm. Even after Curley is physically and mentally humiliated by Lennie in the bunkhouse fight, his worst instincts are on display in chapter five after his wife is found dead. Rather than mourn his wife, as any caring man might do, he can only think of revenge and how he will kill Lennie. Like Tybalt he cannot accept an insult or a chance at gaining revenge.

Curley might also be considered a misogynist, maybe the worst masculine impulse. His wife is obviously lonely and admits that she doesn't even like him. Steinbeck suggests that Curley mistreats her and probably even cheats on her by going to the whorehouses in Soledad. Steinbeck portrays Curley as the stereotypical bully. Unlike most of the other characters in the book, Curley has no redeeming qualities and is one dimensional in the same way as Tybalt. They are negative in their masculinity because that is what the plot needs. Because each story is considered a tragedy, an antagonist, such as Tybalt or Curley, is all important.