We all strive for success (and should) in everything we do. It's just common sense that we want to be successes rather than failures in what God has called us. However, the moment when we become possessive of that calling, or we forget why we started in the first place, is the moment we open up to the door to temptations and any other thing that wants to see us crash and burn. Your calling is unique to you, which is why you are the only one who can steward it.