He laughed. She was looking at him so earnestly. It just slipped out. She was a genius but she didn't know how to park right? Driving home later, he felt bad but guilt quickly turned to annoyance. Couldn't she understand sarcasm? Surely she could define it according to Webster's, the Oxford English Dictionary and the Journal of Brain Conditions for Smart-Asses.
Maybe his problem was her automatic acceptance: if he said it, it was true. She was so closed off, but she had decided to put her faith in him. He only hoped he was up to the challenge.