Via The Onion:

It could be anything—music, writing, drawing, acting, teaching—it really doesn’t matter. All that matters is that once you know what you want to do, you dive in a full 10 percent and spend the other 90 torturing yourself because you know damn well that it’s far too late to make a drastic career change, and that you’re stuck on this mind-numbing path for the rest of your life.