Description taken directly from wikipedia:
Someone who engages in passive-aggressive behavior will typically not confront others directly about problems, but instead will attempt to undermine their confidence or their success through comments and actions which, if challenged, can be explained away innocently so as not to place blame on the passive-aggressive person.
In some instances of passive-aggressiveness, the person will solicit the confidence of others as to their ability to perform duties, and then purposely sabotage those duties through procrastination or mishandling responsibility. Subsequent demands for performance are laid aside with claims of interference by the demanding parties or some other condition outside the control of the influence of the person who is engaging in passive-aggression, when in fact the delays and poor performance are due to the person's internal perception that to perform the task at another's demand is a demeaning insult to them. The omission of performance leaves the person in control of the situation, and allows that person to continue the aggressive behavior toward others. In cases where passive-aggression behaviors may indicate a personality disorder, these behaviours can persist even if it means personal loss to the passive-aggressive person, i.e. job loss or loss of esteem by others.
Some passive-aggressive behaviour may result from society's conditioning of individuals; direct confrontation can lead to harmful consequences. For example, confronting one's manager may lead to the loss of opportunities, such as being passed over for a promotion or even losing one's job. Not all passive-aggressive behavior is problematic or a sign of a disorder, but it may still lead to isolation from others due to frustration from dealing with the passive-aggressive individual.
Often passive-aggressive behavior manifests itself in individuals who view themselves as "peaceful". These individuals feel that expressing their anger through passive-aggressive behaviour is morally favorable to direct confrontation. Indeed, there are many cases where passive-aggressive behavior may be more effective, and in that sense more rational, than direct confrontation.
*thank you wikipedia for clearing up the inevitable...and for this knowledge on human behavior - good 2 know why it takes place!
