Procrastination is the practice of carrying out less urgent tasks in preference to more urgent ones, or doing more pleasurable things in place of less pleasurable ones, and thus putting off impending tasks to a later time, sometimes to the "last minute" before the deadline.The pleasure principle may be responsible for procrastination; one may prefer to avoid negative emotions, and to delay stressful tasks. The belief that one works best under pressure provides an additional incentive to the postponement of tasks. Some psychologists cite such behavior as a mechanism for coping with the anxiety associated with starting or completing any task or decision. Steel indicated in 2010 that anxiety is just as likely to get people to start working early as late and the focus should be impulsiveness. That is, anxiety will cause people to delay only if they are impulsive.Schraw, Wadkins, and Olafson in 2007 proposed three criteria for a behavior to be classified as academic procrastination: it must be counterproductive, needless, and delaying. Steel reviewed all previous attempts to define procrastination and in 2007 indicated it is "to voluntarily delay an intended course of action despite expecting to be worse off for the delay.". Sabini & Silver argued that postponement and irrationality are the two key features of procrastination; putting a task off is not procrastination, they argue, if there are rational reasons for doing so.Procrastination may result in stress, anxiety, a sense of guilt and crisis, health problems, and severe loss of personal productivity, as well as social disapproval for not meeting responsibilities or commitments. These feelings combined may promote further procrastination. While it is regarded as normal for people to procrastinate to some degree, it becomes a problem when it impedes normal functioning. Chronic procrastination may be a sign of an underlying psychological disorder. Such procrastinators may have difficulty seeking support due to social stigma and the belief that task-aversion is caused by laziness, low willpower, or low ambition. On the other hand many regard procrastination as a useful way of identifying what is important to us personally as it is rare to procrastinate when one truly values the task at hand.