We all need excellent client relation skills, also known as customer service or customer relationship management. These clients we need to deal with can be from all kinds of locations.
They can be within the same company and rely on your services. They can of course be outside customers or clients that have hired you or purchased something from you.
They can even be your supervisors. Anyone that needs something from you can be considered a client.
The bottom line is you want them to want to stick around!