Job satisfaction

The standard work week in America is 40 hours, and demanding careers can require 60 hours/week or more. So you'll probably be spending at least 35% of your waking hours at work, and possibly more like 50% of your waking hours. As such, your job experience will be a major input into your life satisfaction.

Surveys (for example, [http://www.forbes.com/sites/susanadams/2012/05/18/new-survey-majority-of-employees-dissatisfied/ this one) have found that almost 50% of American workers say that they're unsatisfied with their job. It's possible that the people who are unsatisfied with their jobs would be unsatisfied with any job, but the survey results still suggest that career choice can have a big impact on your job satisfaction.