I would argue that stress is the effect of having to do something that you do not want to do. In a work situation you are given a task that you feel inadequate to cope with, or which you simply don't want to be party to but are unable to say no. It may even be something you enjoy doing, but not for 12 hours a day. Stress is an effect of an imposition that is overloading your capacity to fulfil what is demanded of you and preventing you from doing what you really want to do. You are constrained by external forces which impinge on your personal time and space, on the activity of your personal energy field.
Stress is also an indicator of boundaries.
We can build a picture of what we are comfortable with in our sphere of energy, and what we find stressful. We can sense which external influences encourage a sense of fulfilment, and which diminish and disempower us. It puts us in a strong position to choose a path through life. It is certainly rare to feel completely stress free. Indeed, it could be argued that a lack of stress might be an unhealthy condition, seen from the esoteric perspective.