In "Child's Play", why did Chucky hurt John?
Answer
Wouldn't Tell How To Escape Body
In "Child's Play," Chucky hurt John because John would not tell him how to escape the doll's body.
John was Charles Lee Ray's former voodoo instructor, and Chucky turns to him after discovering that remaining in the Good Guys doll is making him increasingly human. Chucky wants to return to a human body before the transformation becomes permanent.
John initially refuses to help. Chucky then uses a voodoo doll to torture him, compelling him to reveal the ritual's crucial condition: Chucky must transfer his soul into the first person to whom he revealed his true identity. That person is Andy Barclay, which explains why Chucky begins pursuing Andy so relentlessly.
The answer is sometimes oversimplified as Chucky hurting John merely for revenge. Although Chucky is violent and self-serving, the immediate motive in this scene is extracting information about escape from the doll. John survives long enough to warn Karen and Detective Norris that Chucky can be killed by destroying his heart.