why tybalt is a trouble maker

Tybalt is a hothead and a tough guy. Unlike his character foil Mercutio, Tybalt doesn't have a sense of humor. Tybalt threatens Mercutio because it is basically what he does. He is "Prince of Cats" tough guy for the Capulets. Hating Montagues is part of his identity. Mercutio knows exactly how to exploit Tybalt and get him agitated. Tybalt tries to disturb the Capulet banquet by going after Romeo but Capulet stops him. Similarly Tybalt provokes a fight with Romeo and then subsequently Mercutio.