Confusing

Date of occurrence:
June 29, 2017.

Kc has gone to Cub Scout Resident Camp, while Leo stays with us. We are all sitting in the living room and Opa decides to play a joke on Leo.

Opa, out of the blue: "What did you call me?"
Leo: "I called you nothing."
Opa: "You call me nothing? You better not call me nothing, boy. I am something."
Leo, not quite getting it: "I called you nothing!"
Opa: "You are doing it again. Don't call me nothing. I am something. What did you call me?"
Leo leans all the way back in the chair, grabs his head and states the obvious.

Leo: "Confusing!"