Passive-aggressive behavior refers to passive, sometimes obstructionist resistance to following authoritative instructions in interpersonal or occupational situations. It can manifest itself as resentment, stubbornness, procrastination, sullenness, or repeate failure to accomplish requested tasks for which one is, often explicitly, responsible. It is a defense mechanism and more often than not only partly conscious. For example, people who are passive-aggressive might take so long to get ready for a party they do not wish to attend that the party is nearly over by the time they arrive.