“I’ll try to catch him,” said Curley. His eyes passed over the new men and he stopped. He glanced coldly at George and then at Lennie. His arms gradually bent at the elbows and his hands closed into fists. He stiffened and went into a slight crouch. His glance was at once calculating and pugnacious. Lennie squirmed under the look and shifted his feet nervously. Curley stepped gingerly close to him. “You the new guys the old man was waitin’ for?”

– John Steinbeck

Of Mice and Men, Chapter 2. Curley is a short aggressive man who feels he always has to prove himself because of his size. He has a built-in readiness to fight.