"Only when the person's plain or the remark rude. Note the alliteration."
"What are you going to do?
"Obey orders, I suppose." said I, pointing to the door.
"'Wait until the train stops?'"
"I think so," said I, looking at the flashing hedgerows.
"You see, I've given up acting for the pictures. Otherwise, I should adjust my handcuffs, run along the foot-board, and dive in the direction of the nearest pond."
"While I—?"
"Lay perfectly still. You see, I should be carrying you in my teeth."
"Thanks awfully."
"Not at all. It's a great life."