The Truth Robot

Robots, they smack the truth out of you.

One day, a dad brought home a robot that would slap anyone who told a lie. Dad (to son who just came home): "Where have you been?" Son: "College?" (The robot slaps the son.) Dad: "I was very disciplined and talented at your age." (The robot slaps the dad.) Mother (laughing): "That's because he's your son." (The robot slaps the mother.)