I hire people. I ask this question because I sincerely want to know if there is a good fit. If you are honest and I am honest then we start off a little better with a higher probability of having a good working relationship.
I also ask this because I want to know if you are a curious, growing, learning organism. We want those. We don't want 9 to 5 people. Tell the truth. Why start off lying?
The truth will come out soon enough. Why hang out for a few weeks and get bounced because of a wrong fit? It's bad for everyone.
But then that's our shop. We do it our way. In Dilbertville it is probably different. But you get to choose your life, so why not do it right?
EDIT: if you answered me "I like programming. You're hiring programmers" and you showed me you really did like it, that would be a winning answer in my book. I hire tax professionals. Someone who says they really really like the hard core "work out the numbers" paperwork would be exactly what I want. Or someone who loves to figure out seemingly intractable problems.
So I think your throwaway answer is probably the best one. Say it with a laugh and then follow up with something that shows you REALLY like programming. Winner.