Sunk cost is when you have to fire a client because it creates more trouble than what is needed. You have to take a loss but it's for the good of the business. I have to fire a client once every two years. It never feels good, as I feel I could have handled the client better, I could have seen it coming, I could have acted differently. But in truth, I never know what to expect from a client. It's hard to tell really with the first couple meetings. Last week I had to fire a client. It happened nicely though, she hinted that the work wasn't going the way she expected and said that she could take her business somewhere else. I jumped on the offer since I was thinking the same. I became a lot more productive today. I realized how it was an uneeded stress, even if the works wasn't that stressful. I really have to work for the people I feel connected to, with meaningful work. There are plenty of people that needs my services, I don't need to say yes to every contract that comes my way anymore...