Good points. We recently fired one website client:

The former client is a prominent Hollywood actress who personally objected to paying pre-approved invoices, many involving less than $100 in service. Her after-hour calls to staff, and last minute requests began to negatively affect the entire eBusiness division - as she was sometimes caustic. When 2 staff members asked not to work with her because of her attitude, we asked her to find a new company. She was Shocked! Apologetic! …and just as we were about to keep her on, her old self emerged.

Since we fired her, the division staff morale soared.