Low opinion

     "I have an idea that you saved me a good deal of trouble by taking me home," he said. "I'm grateful to you for that.'

    "Don't be grateful," she said. "I've an idea that you can look out for yourself very well, Mr. Hitchings."

    "Then you have a higher opinion of me than I have," he said.

    "I hope not," she answered, "because I have a rather low opinion."

(from Think Fast, Mr. Moto, by John P. Marquand)