Awhile back, as I was struggling to figure out my writing life, I became enlightened to what writing means to me. I asked myself this question: If someone said to me, "Look, I'll give you a million dollars right here and now, but the only thing you have to do is never write again," would I take it? I immediately knew the answer...'No'. I wouldn't take the money (aside from extreme circumstances involving family, of course).
To live a life without writing would tear me apart. At that very moment I knew that writing was my life purpose and there was no way I could back down from it.
I think this is an excellent way to determine what we are all passionate about. What would we give up to ensure we live out our passions and our dreams?