I'm all too familiar with these types of people - very prominent when I began doing freelance work.
As someone above mentioned, I think it comes down to client management skills. As a beginner, I didn't want to be seen as the 'bad guy', especially with close acquaintances, but there's only so much stress one can endure before they have to put their foot down and nip the problem.
My advice is simple: If the work isn't worthwhile, don't do it. I had to learn this the hard way.