Imagine how your legs feel when you stand up after a long road trip. Your knees pop and your muscles burn. Once you straighten your back and let out a good yawn, your body feels functional again. Mentally, you feel freed from the confines of that prison on wheels.
Turn that road trip into a 40-hour workweek and you'll understand how some people view cubicle jobs. The prospect of sitting at a desk (probably in front of a computer), with only a thin partition separating you from a sea colleagues is sometimes too much to bear. No freedom to roam anywhere except the fluorescent-lit hallway.