Interviewer : "Why do you want to work for us?"
Applicant : "Let me tell you something. I responded to an advert which made the company sound like a market leader and the position one which I would find interesting and enjoyable. After sitting in your tatty reception area and listening to the receptionist's inane personal conversations and babbling whilst you kept me waiting for over half an hour after the agreed time to see you, when I had the courtesy and foresight to arrive early for the appointment, and I wasn't even offered an apology, let alone a cup of tea, I don't want to work for you. I have seen how you treat potential employees and customers and it's not for me.
Interviewer: "So you're not interested in the position?"
Applicant : "Does it sound as if I am?"
Interviewer : "No, but you might be the right person to help us to improve our own working conditions and the perception people have of us."
True story, because I was the applicant! And I didn't take the job.