Sources of frustration may be internal or external. Internal sources of frustration involve personal deficiencies such as a lack of confidence or fear of social situations that prevent one from reaching a goal. Conflict can also be an internal source of frustration when one has competing goals that interfere with one another. External causes of frustration involve conditions outside the person such as a blocked road, lack of money, or lack of sexual activity.
In terms of psychology, passive-aggressive behaviour is a method of dealing with frustration.