I realize that title sounded a little harsh, but I know someone out there needed to hear it. If you've been in business for yourself for any length of time, you've likely learned a lot about who you like to work with and who makes your life miserable. I know I've learned this lesson myself. In the beginning, it was painful. Now, I'm starting to recognize the traits that will make my professional life (and, therefore, life in general) a living hell. And I'm quick to walk away.