Apparently, it should be defined, since it seems that some respondents only know (as I only knew) bits and pieces of what it is. So, from Wikipedia:
Passive-aggressive behavior is a general term used in many contexts.
According to some, passive-aggressive behavior can manifest itself as learned helplessness (in which an organism has learned to be helpless because proactive behavior is useless), procrastination, hostile jokes (though jokes in general are recognized as a method of expressing veiled hostility), stubbornness, resentment, sullenness, or deliberate/repeated failure to accomplish requested tasks for which one is (often explicitly) responsible. According to Living with the Passive-Aggressive Man, a self-help book, a passive man does little to get what he wants as it is too much effort to do so, and ranges from the inept “loser” type to the conformist who does anything to be liked, avoids making waves and rarely says what he feels.
In psychology
In psychology, passive-aggressive behavior is characterised by a habitual pattern of passive resistance to expected work requirements, opposition, stubbornness, and negativistic attitudes in response to requirements for normal performance levels expected of others. It occurs in the workplace or interpersonal contexts, but behavior is not considered passive-aggressive if exhibited during a Major Depressive Episode or cannot be attributed to Dysthymic Disorder. Most frequently it occurs in the workplace where resistance is exhibited by such indirect behaviors as procrastination, forgetfulness, and purposeful inefficiency, especially in reaction to demands by authority figures.
Another source characterizes passive-aggressive behavior as: “A personality trait marked by a pervasive pattern of negative attitudes and characterised by passive, sometimes obstructionist resistance to complying with expectations in interpersonal or occupational situations. Behaviors: Learned helplessness, procrastination, stubbornness, resentment, sullenness, or deliberate/repeated failure to accomplish requested tasks for which one is (often explicitly) responsible”.
Passive-aggressive may also refer to a person who denies (in the sense of “refuses to acknowledge”) his or her own aggression (in the sense of “agency”), and who manages that denial by projecting it. This type of person insists on seeing himself or herself as the blameless victim in all situations.
These may not be complete and comprehensive definitions, but they are very illustrative.
So, according to this, the teenager (or husband, or anyone) who agrees to take out the trash and then continues to walk by it and not take out the trash is definitely exhibiting passive-aggressive behavior.
The workers who appear to listen to a technician and appear to understand what he’s saying and in fact demonstrate understanding… and then go back to old ways of working when he leaves that area… those people are passive-aggressive.
I don’t want to give too many more examples, because they’d probably hit too close to home and offend too many jellies if I started pulling from examples that we can all see here in Fluther (including my own, and probably including this non-example, too).