Ilchi lee explains about how our brain works.
…Did you ever think that when we naively make comments like “I’m unlucky and lack ability. I will fail”, such outcomes are destined to become reality? But there is no need to worry because our brains contain the functions of doubt and fear. If something in life is difficult and we say, “Hey! I should just die!”, wouldn’t it be a big problem if such an expression of desire became reality for us right away? So when information is entered into the brain, the function of doubt which is in the neo-cortex askes, “Is this right? Is it safe? Can I do it? Do I really want it?” And even if we think, “It is not safe. I can’t do it” but we still try to do it, then fear in the limbic system prevents us from acting carelessly. But these functions of doubt and fear can alse be obstacles when we are trying to enter information into the brain about things we really do want, such as, “I can do it. I am happy.” So doubt and fear can be guardian angels as well as obstacles.
We feel nervous going down a road for the first time and look carefully as we move forward. But we don’t think anything of going down a well-traveled road and just proceed without caution. The brain is the same way. When making a new choice, we ask all kinds of questions, such as “Is it right?” or “Is it safe?”. But if we continue this same behavior, then it becomes a habit and we just do that action each time without thinking about it. This means that a circuit which has been habitualized in the brain is performed by the brain without doubt or fear. But when making a new dicision which is not an everyday practice, we must overcome the functions of doubt and frear that strongly resist our decision. Therefore, as long as our new decisions don’t include the focusing of energy that is stronger than our daily habits, the brain will continue to perform the daily habits….