After being fired from Apple, a company he founded, Mr. Jobs says
I'm convinced that the only thing that kept me going is that I loved what I did. You've got to find what you love. And that is as true for your work as it is for your lovers. Your work is going to fill a large part of your life. And the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to do what you love. If you haven't found it yet, keep looking and don't settle.