Ajahn Brahm explains that the fear of making a mistake is what makes decision making difficult, and it comes from the conditioning of punishment associated with making wrong choices. The speaker also mentions that whatever decision we make, we can always make something out of it and that life is continuously evolving. When it comes to decision making, it is important to not let personal desire, ill will, delusion, or fear influence our choices. We should learn to make decisions quickly and not be afraid of making mistakes. Many people make decisions out of fear, but we should remember that whatever path we choose, it will always lead to different options and learning experiences. The best way to make decisions is to be well informed and not let fear hold us back.