Is your job your passion?

For most of us, blogging isn't a job.  It's something we do because we feel the urge to write, to communicate, and to share something with the world.  Similarly, and unfortunately, there's often a job we do to pay the bills that perhaps isn't our "passion" in life.  How does your "day job" differ from your passion?  Are they the same?  What satisfaction do you get from your passion that your day job just doesn't offer?