A week ago, a co-worker of mine found out that I write fiction in my free time. They asked me what I wrote. I replied, "Oh, a bit of everything. Except romance." Their response shocked me. They told me the best authors only write in one genre. I've always considered this an effect of the publishing system. I immediately though of Steven King, who, in my opinion, frequently writes out of the "horror" genre he's been type casted into. My mind next went to J.K. Rowling. What do you guys think? Should you become an "expert" so to say in one field, in the belief it will make you better, or continue to give genre classification the middle finger?