The question of the exercise is: What would you do if you knew you could not fail?
The way I'm feeling lately, I would likely choose to energize the political party that shared my progressive views. There is so much apathy and acceptance of the status quo these days. Any dissent is characterized as unsupportive at best and treasonous at worst. The current administration is systematically dismantling any advances made during the previous eight years under a cloak of "National Security" and squashing any public discourse of their obviously short-sighted aims.
In terms of my career goal, however, I would quit my job and write full time. What keeps me from doing that is my need for a consistent income to take care of the responsibilities I have. I have a mortgage. I help care for Ericka. These responsibilities and others cannot be easily laid aside. There must be care taken to insure a good flow of income so that Ericka and I are not endangered.
So what that means, I suppose, is "Don't quit your day job." I can still pursue my goal while maintaining my current position. What it will take, however, is a lot more work. I'll have to, basically, work two jobs until I can become established as a writer.
The good thing about this, though, is that it gives me a concrete goal. I must make $X per month to have succeeded at becoming a full time writer. Also, it allows me to take steady steps towards that goal. As I make more as a writer, I can cut back my hours at my second job, giving me more time to write.
I like that idea because it also is a reward for writing. Each dollar made writing is, essentially, that many minutes less I have to spend in drudgery each day.