“Clients from hell”—that’s what some people call them. And if you stay in business long enough, you’re bound to encounter one. Even relationship expert Andrew Sobel isn’t immune, and that’s why he, along with Jerold Panas, authored Power Relationships: 26 Irrefutable Laws for Building Extraordinary Relationships and the accompanying workbook Power Relationships Personal Planning Guide.

One client, Sobel recalls, started off relaxed and charming but soon morphed into a “mean-spirited tyrant.” When Sobel delivered a memo to him, the client “noticed a typo on the second page and began angrily yelling at me. ‘This is shoddy, unprofessional work,’ he shouted across the table, his eyes bulging and face turning red. ‘How could you show this to me? This is totally unacceptable!’ His rant continued for a full minute.”

So, what to do when you’re faced with a similar situation? Here are three types of tough client and some strategies for dealing with them:

1.    The insecure client. These clients project their insecurity onto you. Because they are afraid of failing, they attempt to micromanage. Insecure clients also find it difficult to trust you and don’t want to try anything new or different.

The prescription: Strive to demonstrate a low level of risk. Reassure them by keeping them apprised at every step of the sales process. Do what you can to demonstrate reliability and consistency. Sobel advises that you “frequently reassure this type of client and give them a sense of control.”

2.    The boundary pusher. This client does not observe customary boundaries. He will call or email you on weekends or at night and expect an immediate response. He will intrude upon your personal time, leaving you feeling pressured and resentful.

The prescription: Alert this client to your boundaries early on. Explain that “on workdays, we respond to emails within four hours unless it’s clearly urgent, in which case we’ll get back to you within the hour. If something comes up over the weekend, unless it’s an emergency, we’ll respond Monday morning.”

3.    The do-nothing client. Some clients simply refuse to move forward and accomplish the tasks they’ve been given. You meet and agree on next steps, but nothing gets done. More frustrating than difficult, this client is nevertheless a headache.

The prescription: Do some probing and find out what’s really preventing your client from acting. Is she actually an insecure type? There are many reasons a client might refuse to move forward, and you need to find out what’s going on to have any hope of fixing it.

Ask if she would like to speak to one of your satisfied clients. “Also, ask yourself if the problem or issue you’re addressing is truly an urgent, important one. Maybe the client’s priorities have shifted. If so, you need to know that so you can help the client accomplish something that does provide value.”

Says Sobel, “Relationships may feel complex and mysterious, but, really, they’re subject to some pretty simple rules. When you learn them, and put them into practice, it can shift your work and your career to a higher level.”

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