A Gallup poll shows that 70% of the workforce either hate their job or was "disengaged" from their work. Most people take a job out of necessity rather than being passionate about that line of work. They settle for a salary as oppose to pursuing their purpose or something they are genuinely passionate about. Sometimes it takes time to find your purpose, but the sooner you discover your gifts, the faster you will find job fulfillment.
If you are working in a job and it's not fulfilling, take on a project that you are passionate about. If you are not getting the opportunity, start your business as a part-time gig until it becomes something you can put your entire focus on.
But don't settle for a job you hate, and don't convince yourself that this job is the only one for you. Life is way too short to live an unfulfilled life. According to Steve Jobs, if you haven't found it yet, keep looking, don't settle, as, with all matters of the heart, you will know it when you find it.