My boss told me he had a mate who was asked what his weaknesses were. He didn't hesitate in answering he didn't have any. The interviewer said, surely you must have one? So he sat for a moment with a thoughtful look on his face and then said with a smile... Nope, can't think of one.
He got the job.
My sister was once asked why she wanted the job and she said "for the money, why else would I go to work?" She also got the job (but it was in a supermarket so I don't think they were looking for rocket scientists).