Stressors lead to stimuli which evoke some kind of a response. Whether your response is physical or psychological, stressors require that we adapt and respond in some way. The greater the gap between the demands and the resources, the more stressful a situation becomes for us.
Some stressors are small, like finding there is no toilet paper when we go into the bathroom, or calling someone and their voicemail is full. Farther up on the scale, there are major negative events, like being caught in a storm and unable to get home through downed power lines, or being the victim of a crime. Looming larger are catastrophic events, often unexpected, such as natural disasters, acts of wars, or riots.
Events over which we have very little control, which occur suddenly and unpredictably, and which have an impact that lasts for a long period of time, generally have the biggest impact on physical and emotional health. In addition, even small events that are chronically repeated over a long period of time (like your colleague being late for work every day for a prolonged period) can be equally taxing.
