According to the POSIWID principle, the purpose of some complex artefact or phenomenon is what it does. There are people who see positive value in stress. There are also people who, while claiming to dislike stress, still act in ways that increase stress for themselves and other people.
Fight / Flight - Stress provides energy for contingencies and emergencies. It may unlock hidden reserves of power and creativity.
Selection - Stress may act as a selection mechanism. It identifies and promotes those tough enough to withstand stress.
Motivation - Stress may act as a stimulant. Some managers deliberately put their staff, suppliers and other people under stress, in the belief that this will produce better outcomes.
Pleasure - Freud's pleasure principle is based on the balance between excitement and calm.
Trust - Perhaps the most effective way of establishing authentic trust between individuals and teams is to have a shared experience of stress. This is sometimes called "going though fire together".
Explanation - Like many other psychosocial phenomena, stress is a totem in some organizations (in other words, held up as a cause and explanation of all sorts of phenomena), and is taboo in other organizations (in other words, not able to be acknowledged or cited as an excuse). The effects and symptoms of stress are likely to be very different between these organizations.
Roger Dobson, Does stress help us succeed? (Independent, 4 May 2011)