Your mind is an instrument, a tool. It is there to be used for a specific task, and when the task is completed, you lay it down. As it is, I would say about 80 to 90 percent of most people's thinking is not only repetitive and useless, but because of its dysfunctional and often negative nature, much of it is also harmful. Observe your mind and you will find this to be true. It causes a serious leakage of vital energy.
For many people, the first indication of a spiritual awakening is that they suddenly become aware of their thoughts. They become a witness to their thoughts, so to speak. They are not completely identified with their mind anymore and so they begin to sense that there is a depth to them that they had never known before.
To go out of your mind once a day is tremendously important, because by going out of your mind you come to your senses. And if you stay in your mind all of the time, you are over rational, in other words you are like a very rigid bridge which because it has no give; no craziness in it, is going to be blown down by the first hurricane.
Essentially Satori is a sudden experience, and it is often described as a "turning over" of the mind, just as a pair of scales will suddenly turn over when a sufficient amount of material has been poured into one pan to overbalance the weight in the other. Hence it is an experience which generally occurs after a long and concentrated effort to discover the meaning of Zen.