People are fulfilled when they see something tangible as a result of their efforts. Sitting in a cubicle "processing" a ceaseless torrent of bullshit busywork is what causes people to be depressed and hate their job.
If you're lucky you can work on projects that tax you mentally, include some outdoors/physical element, and actually make something tangible at the end but if not then you'd do better working in a factory mindlessly assembling components than mindlessly sending emails, because at least you're standing up and you can point at what you did today.