Me: “If I can just get your signature there…”

Elderly customer: *scribbles his name, then starts drawing on the counter*

Me: “Uh… sir?”

Elderly customer: *starts drawing up the side of the cash register*

Me: “Sir? You just… sign your name.”

Elderly customer: *doodles in the air, up and up… and then jabs me in the forehead with the pen and draws lines on my face*

Me: “What the h***?”

Elderly customer: “Reactions like that would have gotten you killed in the war!”