The Appeal by John Grisham. After building some wonderful characters who were struggling to survive following multiple cancer deaths caused by illegal dumping of poisons, he let the bad guy win and become even richer than before, while leaving everybody else wallowing in poverty and sickness.
I suppose his rationale would have been, "Well life's like that." But that wasn't life, it was fiction, and after staying with his protagonists throughout I felt robbed. I threw the book in the trash and will NEVER read another Grisham story.