About Not Disappointing the Reader

I recently read a comment on Goodreads in which a reader was upset by an ending because it did not fit the genre formula. I gather it was a romance or relationship story that had the opposite of a happy ending. Okay. I get it. Life does not always produce happily-ever-afters. However, I understand the reader’s disappointment/outrage. In a sense, she was sold a story under false pretenses. She invested considerable time, immersed herself in the story, endured (vicariously) the hopes, fears, disappointments, perils, and uncertainty of the main character. Those of us who really enjoy reading (make that becoming the main character), understand her feeling of betrayal when things did not turn out as expected/deserved.

So here’s the question: does the author owe it to the reader to stick to genre formula? Is it betrayal to make the story more life-like by having it all continuing to go to crap instead of rewarding the long-suffering heroine/reader with what she deserves rather than what life is more likely to throw at her?

I think it all depends on the packaging and marketing. If it is wrapped in Romance cover art, it should probably stick to the genre format. If it is advertised in such a way as to lead the reader to believe he/she is buying a happy ending story, it ought to deliver one. (Disclaimer: since I know little of this genre, I’m not sure of the acceptable variations of plot and formula, so I may be missing something.)

Of course, creativity is all about breaking the mold and devising new formulae. Thoughts?