I have the opposite effect - When I don't need to make money I forget everything I want to do. Because the things I love doing involve working hard, finding new solutions for problems, digging my way out of a tough situation, working with a team, etc. I thrive in a work environment and suffer miserably when left to myself.
I don't think this has anything to do with money. He's not saying that what you come up with is what you should do full-time as a way to earn money. He's just trying to make you come up with what you're good at. If you didn't have to worry about money at all, what do you think you'd be doing? What is it you would enjoy and love? Whatever that is, you're probably good at it because you're passionate about it.
Basically it is this, if you didn't have to worry about money at all, what do you think you'd be doing? What is it you would enjoy and love? And whatever it is you come up with, it's something you're good at because you're passionate about it.
This is my favorite excersize, mostly because I would be doing exactly what I'm doing now, Drawing!! (Of course. . . I could do without the getting up at 6am, and the hour commute, and the overtime hours. . .)