Happiness is subjective, especially when it comes to those factors that bring people contentment with their work.

Nevertheless, an online career community called CareerBliss has compiled data to rank the happiest and unhappiest cities in the U.S. in which to work. The information is based on analysis from more than 200,000 independent company reviews. The company evaluated eight factors that affect happiness with work: growth opportunities; compensation; benefits; work-life balance; career advancement; senior management; job security and whether an employee would recommend the company to others.

If you're stuck in a job-search rut, here's a tip: the newspaper is a great place to look for leads.

If you want to take your career to the next level, the advice we seek and get usually has a practical bent: network, research the industry and prospective employer, ask for feedback, pursue training and education opportunities, work on being an effective leader. These are all good things, but in this month's Harvard Business Review, psychiatrist Edward M. Hallowell shows how understanding brain activity can lead you to a more systemic approach to succeeding and advancing in your career.

When we think of great leaders, those that come to mind first -- say, Jack Welch, Steve Jobs, or Martin Luther King, Jr. -- tend to be charismatic, larger-than-life figures. Such examples have led to the popular belief, particularly in business, that extroverts have an advantage in their careers. Those who are outgoing, unafraid of the spotlight, and speak their minds and give direction are natural leaders, the conventional thinking goes. While this isn't necessarily wrong, nor is it the whole story, according to researchers from the University of Pennsylvania's Wharton School, Harvard Business School, and the University of North Carolina's Kenan-Flagler Business School. Introverts can be equally effective leaders, says Wharton's Adam Grant, lead author of "Reversing the Extraverted Leadership Advantage: The Role of Employee Proactivity" in a forthcoming issue of the Academy of Management Journal. Interestingly, Grant and his colleagues find, neither extraverts nor introverts perform better in productivity or profits. Instead, the real indicator of success lies in the pairing of each type of leader with different types of employees.

Life isn't always fair, certainly not in the job market. We've all been exasperated when a seemingly undeserving competitor gets a plum job or promotion. If it seems that style and presentation often trump real substance, it's because they do, according to research from Harvard Business School.

Not long ago I was on the phone with the CIO of a major professional sports organization. During our conversation she shared that she was at the time fielding applications from experienced IT professionals, contractors who would normally charge upwards of $30 per hour for their services. They were facing a job market so bleak they were now sending her their résumés for internships designed for college students that paid around $10 per hour.