The thing about letting the situation do its work though is that you don't know what you'll get?
If I want a career as a writer or musician, I have to set goals and follow through on things, otherwise I'll just be sitting around waiting for things to happen.
I have yet to meet a musician who has "made it" by waiting for something good to happen.
Goals ARE fulfilled when you follow through. That's just planning. If you wanted to take a vacation, you'd plan it out, right? Not just show up at the airport? That's all goal setting, just on a smaller scale.
Of course, those are just my thoughts ;D