Slim, the person who is worshiped on the ranch, and Carlson, the guy with the gun, tell Candy, an old ranch worker, to get rid of his dog because it is to smelly. Candy cannot shoot it himself, however, Carlson volunteers and kills the old dog. Candy tells George, "I ought to of shot that dog myself, George. I shouldn't ought to of let no stranger shoot my dog." (Chapter 3)
Curley, the boss's son, begins to suspect that Slim is having an affair with his wife. He expresses he wants to fight by continuing and continuing to bother Slim with this, and it starts to escalate.
Curley starts to pick at Lennie and clearly wants to fight when finally, George yells, "GET IM LENNIE!" and Lennie punches him right in the face.