How can I deal with an “impossible” client?
There are many reasons why a client may come across as "impossible." First, determine if this is truly an impossible client or if the relationship just needs to get put on a better footing. If it’s the latter, then you need to conduct a relationship review with the client. Gain a better understanding of the client‘s expectations for how they would like to work with you, and reaffirm their agenda of key priorities. Talk about how you work with your "best clients." Reiterate what you expect of their organization–what they need to contribute to make the collaboration truly successful.
If the client is a tyrant or otherwise difficult to work with, you have to either confront them with their behavior or simply let the account die of benign neglect. One of my clients told me this story: "We had one of these impossible clients, a CEO who mistreated our people, constantly squeezed our fees, and was otherwise difficult and demanding at every turn. I sat down with him one day and said, candidly: ‘Look, I think you should fire us and find another provider. The truth is we’ve lost a number of young associates from the firm because of the harsh treatment they’ve received on your account. The relationship isn’t very profitable for us, because you’ve squeezed our fees so much. At times you’re unreasonably demanding.’ He looked up at me and said, ‘Well, I guess I need to tone down my bluster. I figured I’d be called on it eventually.’ After that he still was occasionally hard to deal with, but the relationship improved dramatically, and he remained a loyal client of mine for many years. I still stay in touch with the guy."