Everyone experiences pressure at some time in their life and problems arise when pressure is excessive, prolonged, or comes from too many directions at the same time. Most people can deal with high levels of stress and sometimes even thrive on it, but when additional pressures or crises occur, some people find it more difficult to cope with and therefore find it a stressful experience.
What is important is the individuals perception of the situation. It is not so much the situation that causes the stress, but how we perceive it and what we bring to the situation in terms of our mental attitude and past experiences etc, that is largely the problem.
So what is stress?
One definition is that " stress is the result of an imbalances between demands and resources" - but it is also about the individuals own perceptions about those demands and resources that are important. Another definition is that "stress normally occurs when the perceived pressure exceeds the individuals ability to cope" but again there are real pressures in the workplace and perceived pressures based on the individual's belief and perception of their own ability to deal with the issues they are faced with.