This comment from Steve Jobs (via my friend David Pottinger) in a great article by Stephen Fry on the Launch of the iPad: "I don't think of my life as a career. I do stuff. I respond to stuff. That's not a career -- it’s a life!" really resonates with me. I like the concept of just "doing stuff" - love that fuzzy word "stuff".
People are always telling me that if I wish to build a business I should do "x, y, z" and I reply "I am not looking to build a business I am looking to do stuff that I enjoy and earn a living in doing it".
To my mind, life is not a career, its not a business, its not a profession - its just about doing fun worthwhile stuff!