Stressors are those events or situations which cause one to feel tense or strained (stressed).
There are numerous categories from which stressors stem, amongst them are: frustrations, conflicts and pressures

Frustrations are felt when a person is unable to meet his or her needs and/or when a goal is blocked by obstacles. It also occurs when there is no ultimate goal in mind. Frustrations lead to self-devaluation and other feelings of low self-worth and incompetence. Frustrations can stem from:

(a) environmental/circumstantial frustrations: such as experiences of prejudice (racism, sexism, bias toward handicapped people, etc), unfulfilling jobs and deaths of loved ones.
(b) internal frustrations: such as perceived or real personal limitations, inter alia handicaps, perceived lack of value, competency and "likeableness".

When I can't choose between two conflicting situations, I get stressed!

Conflicting situations: these can be internal and/or external. External conflicts refer to those arguments/fights that one has with peers, families, spouses, etc. Internal conflicts occur when one has to make a choice between two or more options that have arisen. Once a choice is made, frustration can be felt because of the restrictions of that choice. During the choice-making process, the cognitive (thinking) and emotional minds are strained.

Pressures can also be internal or external and usually result in the need to speed up, intensify work or change the direction in which one is heading to achieve an ultimate goal.

An example of an external pressure is when a student goes through her school career being constantly pushed by her parents to do well. An internal pressure is when the person pushes herself to do well to the extreme. Self-induced pressure, or high motivation, sometimes results in unnecessary stress if time or energy is not managed and one's life becomes unbalanced (i.e. all work and no play!).

Just because stressors are placed in different categories does not mean that they are isolated. In real life, one stressor may have elements of all the categories, causing a higher stressful experience. For a more detailed list of stressors, please see our Stress-Response Diagram.