For people in certain careers, a desk is something you literally can't escape. While working at a call center, trading on a computer, or managing a welcome desk, you can't do your job unless you are planted at you desk.
This was true for me when I worked as a work-life counselor at a benefits company call center. Leaving it for even a moment meant I might miss a call and wouldn't be able to do my job. You can read more about this experience here.