Grandpa's Driving

Grandpa was out driving with his 9 year old granddaughter when he beeped the horn by mistake.

She turned and looked at him for an explanation.

"I did it by accident," he remarked.

She replied, "I know that, Grandpa."

He inquired, "But how could you know that?"

She said, "Because you didn't say 'asshole' afterwards."