We all know that confidence is key to success. The problem is, for some of us, confidence doesn't come easy. We may find ourselves second-guessing our decisions or feeling like we're not good enough. So what's the deal? Why don't some people feel confident? And more importantly, is there anything we can do about it? Turns out, there may be a link between our brain and confidence levels – and by understanding this link, we can work to boost our confidence when we need it most.