Job satisfaction is as elusive as any other kind of contentment. Even given the choice, people are notoriously bad at predicting what will make them happy, a state of mind that is probably more a byproduct of internal and external conditions than a directly attainable goal. Yet psychologists persist in trying to tease apart the factors that happiness at work consistently contains. For some, Abraham Maslow's seminal 'hierarchy of needs' accounts for employees' changing demands at work. The uneducated and powerless are content when work offers them the minimum of security, food and shelter. But once satisfied, these criteria lose their potency. Successful employers then need to foster contexts in which employees can satisfy their desire for meaningful social interaction. Worker satisfaction increasingly depends on the right feedback and rewards that will promote a feeling of self-worth. Finally, people will be happy with nothing short of what Maslow calls 'self-actualisation', a luxurious state in which a person is able to act and think at work according to his or her own highest instincts and abilities. Typically, at this stage, the border between work and life becomes fuzzy. This is when one is most likely to experience what psychologist Mihaly Csikszentmihalyi calls 'flow'. Flow is having or being able to create situations in which one can become completely immersed in what one is doing. Individual difference at work was the focus of a recent report published in the American Psychological Association's Journal of Applied Psychology. The study examined the popular 'Big Five' model of personality, which measures traits that are relatively stable over a lifetime and which, broadly speaking, remain valid across cultures. They are extroversion, conscientiousness, neuroticism, openness to experience, and agreeableness. Extroversion had by far the most robust association with happiness at work. Extroverts appear to instinctively put themselves into situations that foster positive feelings. The trait of conscientiousness strongly effects job performance, of course. But it is also correlates with job satisfaction. Unhappiness at work is most linked to neuroticism. Neurotic people, unlike more emotionally stable individuals, seem to instinctively construct or seek out the conditions in which negative feelings are likely to occur. It is almost as if they are more comfortable being unhappy. Openness to experience is linked neither to happiness nor performance at work, perhaps because it is 'non-directional' in the sense that it renders people more susceptible to both positive and negative experiences. It is, on the other hand, linked to greater happiness with life in general. Agreeableness has a weak link with happiness, which is odd because agreeable people are more motivated to achieve interpersonal intimacy, which generally leads to greater levels of well-being. Psychologists have yet to figure out why. Maslow emphasised the universal aspects of satisfaction, Csikszentmihalyi stresses personal vocation and personality. How, one wonders, do these theories relate to laypeople's views about what makes people happy at work? Do most people agree with Abraham Lincoln, who believed that individuals were about as happy or unhappy as they set their mind to be? Or would they say that Lincoln was assigning too much to the individual's power over his or her own destiny? As a psychologist, I would say that probably depends on whether you ask them on a Monday morning or a Friday night. Jean Nicol is a psychologist specialising in issues of cultural identity and change in an era of globalisation