The 'psychology student' (or former student anyway) in me just had to respond to the question of passive aggressiveness...


Behaviors that help identify passive-aggressive behavior:

Ambiguity
Avoiding responsibility by claiming forgetfulness
Blaming others
Chronic lateness and forgetfulness
Complaining
Does not express hostility or anger openly (e.g., expresses it instead by leaving notes)
Fear of authority
Fear of competition
Fear of dependency
Fear of intimacy (infidelity as a means to act out anger): The passive aggressive often can't trust. Because of this, they guard themselves against becoming intimately attached to someone.
Fosters chaos
Intentional inefficiency
Making excuses
Losing things
Lying
Obstructionism
Procrastination
Resentment
Resists suggestions from others
Sarcasm
Stubbornness
Sullenness
Willful withholding of understanding

A passive-aggressive person may not have all of these behaviors, and may have other non-passive-aggressive traits.