One of the biggest contributors to work related stress is boredom. According to those who study the issue, lack of stimulation on the job can affect workers from the highest to the lowest echelons of the work world and can be more stressful and damaging than overwork. On the other hand workers who say they are busy and their workload is heavy may feel more valued by the organization and tend to be happier and more positive.
See "Boredom Numbs the Work World", Amy Joyce, The Washington Post, August 9, 2005