A lesson I keep learning time after time is that the thoughts that we focus on, the fears that we can't stop thinking about, the failure that we think we are doomed to, will come true if that is our focus. It isn't even intentional, but we will start to self sabotage ourselves to make those fears or thoughts come true.
An example is that I have been worried about my business failing. What I realized is that when I focus on that, when that is all I can think about I end up doing the things that will make my business fail. For instance I end up distracting myself with things that don't matter, or think I am too busy to actually take the steps that I need to take. I realized how I was sabotaging myself unintentionally. I want to succeed so badly, but I was getting in my own way.
Don't get me wrong those fears don't go away, but being able to recognize that we are sabotaging ourselves and readjusting our focus on where we want to go and who we want to become really does change the outcome.