Considering how much time most adults will spend in the workplace over the course of their lives (an estimated 25-30 years), it doesn't take much of a stretch to surmise a person’s choice of career plays a significant role in their sense of happiness.
I believe a fulfilling career is something you have the power to create, moment by moment, year by year, and decade by decade. Just as success rarely happens overnight, deriving a healthy amount of satisfaction from the work that you do requires the right mindset.
I recently read Big Magic by Elizabeth Gilbert. She shares her wisdom regarding the choice each of us has between saying yes or no when inspiration strikes. She writes about clearing out obstacles which are preventing you from living your most creative life, understanding that "whatever is bad for you is probably also bad for your work."
There are so many wonderful truths that she offers, but one of my favorites is found on page 63, where she says: "Work with all of your heart because - I promise - if you show up to work day after day after day after day, you just might get lucky enough some random morning to burst right into bloom."