You have a mind, and you should learn how to use it. There are two levels of your mind—the conscious or rational level, and the subconscious or irrational level. You think with your conscious mind, and whatever you habitually think sinks down into your subconscious mind, which creates according to the nature of your thoughts. Your subconscious mind is the seat of your emotions and is the creative mind. If you think good, good will follow; if you think evil, evil will follow. This is the way your mind works.
The main point to remember is once the subconscious mind accepts an idea, it begins to execute it. It is an interesting and subtle truth that the law of the subconscious mind works for good and bad ideas alike. This law, when applied in a negative way, is the cause of failure, frustration, and unhappiness.