One Book?!

I'm shocked by the fact that every time I reluctantly tell someone that I'm working on a second book, they're even more surprised than when I informed them about my first book. Furthermore, I'm shocked by someone who only writes one book - even if the author's subsequent books were unpublished. I can completely understand how one could have a single book published and have a stack on unpublished manuscripts, but to literally only write one book is surprising to me. However, I can understand how someone could fall into a trap and cease writing to avoid "rejection".