I just saw this video from Super Soul Sunday, where Oprah discusses with author Steven Pressfield the reason why she had such difficulty writing her Harvard Commencement speech. She has spoken and done speeches many times before but this one she couldn't bring herself to write. Pressfield explains that this is an example of resistance, "the more important an activity is to your soul's evolution, the more resistance you will feel to it. The more fear you will feel."
Which is why Oprah was having difficulty, because speaking at Harvard clearly meant something to Oprah. She admitted that it's the name "Harvard" and all that it represents and means.
How many of us want something so deeply, but have not made any moves to make it happen in our lives. We say we want to lose weight but continue to stop at the drive-through every lunch break, or we say we want to write a book but have yet to allow our pen to hit paper.
Pressfield says that the way to overcome resistance is to really realize that the pain of not doing what you really want to do is way worse than the pain of just doing it. So his advice is simple, just do it.