This blog post Why Passion is More Important than Personality in Your Career on Inc. offers some fresh ideas about how being an introvert vs. extrovert relates to career choice- interesting! On a related note, it is usually advised that following one's passion is a great thing to do, because if you are excited, you will be motivated to work hard, so results will follow.
I'd like to play devil's advocate. For many people, might it be better to decouple your passions from your earnings, at least initially in your career? Do whatever makes enough money to create a financial safety net. Then work on those passions from a perch of economic security. Choose projects based on what they are and your role in them rather than the salary, benefits, commute, or other factors not directly related to the passion. Manage your own economics vs. daily satisfaction levels like a business case- with a cool head analyzing the facts, risks and opportunities.
Not saying it can't be done, doing what you love under ideal conditions- plenty of wild success stories out there. Yet too often when pursuing a passion people find themselves at dead ends. It's happened to me, family, friends. Specializing in narrow subject matter area or function can result in a very job limited market. This is a risky position to be in- being dependent on a few niche employers (or target market, if small business) may mean unemployment, underemployment, having to move to undesirable locations, low earnings for many years, lack of growth opportunity, having to travel too much at times it conflicts with home obligations, or other pitfalls.
Focusing too narrowly on passions might also result in overlooking great opportunities to build skill sets, earnings or contacts that could be quite relevant to succeeding at the passion down the road. Or being so invested and passionate that judgment and business acumen may be less than optimal. Why not at least have one economic hedge, whatever it is? While this may sound easier said than done, there are so many fantastic opportunities today to make high earnings online, at a startup that does well, or even at 'regular' jobs.
What has been your experience?