Writing a Hobby?

Recently, in answer to a question, I explained I was a writer.  The woman asked what I wrote and was quite interested in in the writing/publishing process.  At the conclusion of our brief conversation, she remarked it was nice I had a hobby.

I didn't react but I was slightly offended at her perception of writing as a hobby.  In my world, a hobby is something I'd do for relaxation.  I love writing and enjoy it but it's work and I schedule time for it nearly every day.  I don't wait until I have nothing else to do - that would never happen and I'd never write anything!

Have you dealt with people who think writing is a hobby?  How did you feel about it?