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. This kind of compulsive thinking is actually an addiction. What characterizes an addiction? Quite simply this: you no longer feel that you have the choice to stop. It seems stronger than you.
— Eckhart Tolle