Causes of Stress

Threat
A perceived threat will lead a person to feel stressed. This can include physical threats, social threats, financial threat, and so on. In particular it will be worse when the person feels they have no response that can reduce the threat, as this affects the need for a sense of control.
Generally speaking, any threat to needs is likely to lead to stress being experienced.
Fear
Threat can lead to fear, which again leads to stress. Fear leads to imagined outcomes, which are the real source of stress.
Uncertainty
When we are not certain, we are unable to predict, and hence feel we are not in control, and hence may feel fear or feel threatened by that which is causing the uncertainty.
Cognitive dissonance
When there is a gap between what we do and what we think, then we experience cognitive dissonance, which is felt as stress. Thus, if I think I am a nice person then do something that hurts someone else, I will experience dissonance and stress.
Dissonance also occurs when we cannot meet our commitments. We believe we are honest and committed, but when circumstances prevent us from meeting our promises we are faced with the possibility of being perceived as dishonest or incapable .

Life causes
There are many causes of stress in life including:

-Death: of spouse, family, friend
-Health: injury, illness, pregnancy
-Crime: Sexual molestation, mugging, burglary, pick-pocketed
-Self-abuse: drug abuse, alcoholism, self-harm
-Family change: separation, divorce, new baby, marriage
-Sexual problems: getting partner, with partner
-Argument: with spouse, family, friends, co-workers, boss
-Physical changes: lack of sleep, new work hours
-New location: vacation, moving house
-Money: lack of it, owing it, investing it
-Environment change: in school, job, house, town, jail
-Responsibility increase: new dependent, new job

Other stress indicators at work include:
-Sickness absence
-High staff turnover
-Poor communication between teams
-Bullying
-Lack of feedback on performance
-Value and contribution
-Technological change
-Lack of clarity of roles and responsibilities
-Dissatisfaction with non-monetary benefits
-Working long hours
-Boring and mundane work
-One-off incidents
-Uncomfortable workplace
-Lack of training

Watch out for your own stress, and help others reduce theirs.
If you are using stress to persuade, watch for these symptoms as indication of your success. Beware of over-stressing people and creating a fight-or-Flight reaction.