Great advice, our lives are much too short and precious to be spent on people that aren't adding to our success and happiness.
Running a painting and remodeling company I often times run across people that want too much for too little and of course their emergency is our problem. Needless to say, I have turned down more that a few jobs that wouldn't have been worth my time either because of price, or because of the clients themselves.
If we focus on what we love to do, and doing it with people we like, all our lives will run much more smoothly!