I guess Leo Burnett is saying we can try to reach for the stars, but it does not mean that we will actually get there. But it would not be a wasted venture, because we could very well learn a few things that is benefical to us along the way.

Or, you may be searching for that "It Factor" in your life, and you may have to learn to open a lot of doors to get to it; but on your quest to find it, you will be blessed with other gifts.

My answer is along the same lines as Elsa's. What I think he is referring to is when we aim at getting things we want in life, we might not in some cases get those things. However, we will have grown so much from the experiences on the way trying to achieve that goal.

These experiences are priceless in terms of the insights they give us about ourselves.

He was probably trying to say something similar to another saying I like : "Life is a journey, not a destination". In other words, life is all about the experiences we have on the way, and not about the actual physical manifestation of the things we want.

I think he is saying that any progress we make on our journey is never wasted that although we may not get exactly what we wish for we will always receive something beneficial for our growth ( even though sometimes we may not always perceive it that way). Pretty much the same as saying that our prayers are always answered but sometimes the answer is not always what we want but usually when we look back on it, the answer was always the one that had the most potential for personal growth - we just didn't always see it.