Your attitude affects your mood. So why choose to be negative?
M. Scott Peck wrote the book, "The Road Less Traveled." In the first sentence he comments that life is hard, and once you accept that fact you are better able to move forward.
Everyone, regardless of the credentials on the wall, the title or the paycheck, has struggles and disappointments and setbacks. That is just the way it is. There is no Camelot. There is no perfect world. Once you recognize that everyone struggles with the same fundamental issues, it becomes a little easier to move forward.