Editor’s Note: This question was asked on Quora and one respondent, John Joss, had a particularly insightful answer, shown below. John gave us permission to reprint his answer. 
 
John Joss, nonfiction and novel writer, journalist
 
In my experience, few people I have met—when I have admitted to being a writer—have seemed to be fully aware of the extreme work stress often associated with writing. In journalism, meeting an editor’s specifications (length, quality, deadline) can be very stressful, especially when covering a complex story. In freelance assignments of any kind (articles, speeches, proposals, op-eds, advertising copy, promotional writing, whatever), the necessity to deliver results is also stressful, yet none of that will be apparent from reading the end product, which must work properly.

In book writing (I have written almost a score of books), the length of time between start and finish can be prolonged agony, requiring that the writer respond daily, weekly, monthly, even over years, to get it done right, often without any assurance of acceptance. Example: I spent 8,000 hours over an eight-year period researching, writing, editing and fact-checking a fact-based novel that was not, eventually, published (scratch four years’ worth of professional work).

Most people don’t understand these challenges. But they are no different from the challenges in every profession of which outsiders are unaware. It is fair to assume that success in any field is difficult and that the devil is in the details—details that are often invisible to observers.

Source, Quora:  What aspects of a writer’s life are most people unaware of?